NOVA Scientific Calculator<\/title>\r\n\r\n <style>\r\n \/* =========================================================\r\n 01. DESIGN TOKENS\r\n ========================================================== *\/\r\n :root {\r\n color-scheme: dark;\r\n --bg: #0e1117;\r\n --surface: #151a23;\r\n --surface-2: #1b2230;\r\n --surface-3: #222b3a;\r\n --display: #0b0e13;\r\n --text: #f5f7fb;\r\n --muted: #9ba6b5;\r\n --subtle: #6f7b8b;\r\n --border: #2a3443;\r\n --border-strong: #39475b;\r\n --accent: #7ea2ff;\r\n --accent-strong: #5f87ee;\r\n --accent-soft: rgba(126, 162, 255, 0.14);\r\n --danger: #ff8f8f;\r\n --danger-soft: rgba(255, 143, 143, 0.12);\r\n --success: #7fd6a6;\r\n --warning: #f1c46f;\r\n --shadow: 0 18px 45px rgba(0, 0, 0, 0.28);\r\n --radius-xl: 22px;\r\n --radius-lg: 16px;\r\n --radius-md: 12px;\r\n --radius-sm: 9px;\r\n --transition: 160ms ease;\r\n --max-width: 1400px;\r\n }\r\n\r\n html[data-theme=\"light\"] {\r\n color-scheme: light;\r\n --bg: #eef2f7;\r\n --surface: #ffffff;\r\n --surface-2: #f6f8fb;\r\n --surface-3: #edf1f6;\r\n --display: #f7f9fc;\r\n --text: #18202b;\r\n --muted: #596678;\r\n --subtle: #7e8996;\r\n --border: #d7dee8;\r\n --border-strong: #c4ceda;\r\n --accent: #315fc9;\r\n --accent-strong: #244aa6;\r\n --accent-soft: rgba(49, 95, 201, 0.10);\r\n --danger: #b84040;\r\n --danger-soft: rgba(184, 64, 64, 0.10);\r\n --success: #24794b;\r\n --warning: #956900;\r\n --shadow: 0 18px 45px rgba(25, 40, 60, 0.12);\r\n }\r\n\r\n \/* =========================================================\r\n 02. RESET & BASE\r\n ========================================================== *\/\r\n *,\r\n *::before,\r\n *::after {\r\n box-sizing: border-box;\r\n }\r\n\r\n html {\r\n font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, \"Segoe UI\", sans-serif;\r\n background: var(--bg);\r\n }\r\n\r\n body {\r\n margin: 0;\r\n min-width: 320px;\r\n min-height: 100%;\r\n background: var(--bg);\r\n color: var(--text);\r\n line-height: 1.5;\r\n -webkit-font-smoothing: antialiased;\r\n }\r\n\r\n button,\r\n input,\r\n select {\r\n font: inherit;\r\n }\r\n\r\n button,\r\n select {\r\n color: inherit;\r\n }\r\n\r\n button {\r\n border: 0;\r\n }\r\n\r\n button:focus-visible,\r\n input:focus-visible,\r\n select:focus-visible {\r\n outline: 3px solid color-mix(in srgb, var(--accent) 58%, transparent);\r\n outline-offset: 2px;\r\n }\r\n\r\n [hidden] {\r\n display: none !important;\r\n }\r\n\r\n ::selection {\r\n background: var(--accent-soft);\r\n }\r\n\r\n \/* =========================================================\r\n 03. APP SHELL\r\n ========================================================== *\/\r\n .app-shell {\r\n width: min(100% - 24px, var(--max-width));\r\n margin: 18px auto 28px;\r\n }\r\n\r\n .app-header {\r\n display: flex;\r\n align-items: center;\r\n justify-content: space-between;\r\n gap: 16px;\r\n margin-bottom: 14px;\r\n }\r\n\r\n .brand-group {\r\n min-width: 0;\r\n }\r\n\r\n .brand-kicker {\r\n margin: 0 0 2px;\r\n color: var(--muted);\r\n font-size: 0.72rem;\r\n font-weight: 700;\r\n letter-spacing: 0.16em;\r\n text-transform: uppercase;\r\n }\r\n\r\n .brand-title {\r\n margin: 0;\r\n font-size: clamp(1.15rem, 2vw, 1.48rem);\r\n line-height: 1.15;\r\n letter-spacing: -0.025em;\r\n }\r\n\r\n .header-actions {\r\n display: flex;\r\n align-items: center;\r\n justify-content: flex-end;\r\n flex-wrap: wrap;\r\n gap: 8px;\r\n }\r\n\r\n .mode-switch,\r\n .segment-control {\r\n display: inline-flex;\r\n align-items: center;\r\n gap: 4px;\r\n padding: 4px;\r\n border: 1px solid var(--border);\r\n border-radius: 12px;\r\n background: var(--surface);\r\n }\r\n\r\n .mode-button,\r\n .segment-button,\r\n .icon-button,\r\n .soft-button {\r\n min-height: 42px;\r\n border-radius: 9px;\r\n background: transparent;\r\n color: var(--muted);\r\n cursor: pointer;\r\n transition: background var(--transition), color var(--transition), transform var(--transition), border-color var(--transition);\r\n }\r\n\r\n .mode-button,\r\n .segment-button {\r\n padding: 0 13px;\r\n font-size: 0.86rem;\r\n font-weight: 750;\r\n }\r\n\r\n .mode-button[aria-pressed=\"true\"],\r\n .segment-button[aria-pressed=\"true\"] {\r\n background: var(--accent-soft);\r\n color: var(--accent);\r\n }\r\n\r\n .icon-button,\r\n .soft-button {\r\n border: 1px solid var(--border);\r\n background: var(--surface);\r\n }\r\n\r\n .icon-button {\r\n width: 44px;\r\n display: inline-grid;\r\n place-items: center;\r\n font-size: 1.05rem;\r\n }\r\n\r\n .soft-button {\r\n padding: 0 13px;\r\n font-size: 0.82rem;\r\n font-weight: 750;\r\n }\r\n\r\n @media (hover: hover) and (pointer: fine) {\r\n .mode-button:hover,\r\n .segment-button:hover,\r\n .icon-button:hover,\r\n .soft-button:hover {\r\n color: var(--text);\r\n background: var(--surface-2);\r\n }\r\n }\r\n\r\n .mode-button:active,\r\n .segment-button:active,\r\n .icon-button:active,\r\n .soft-button:active {\r\n transform: translateY(1px);\r\n }\r\n\r\n \/* =========================================================\r\n 04. LAYOUT\r\n ========================================================== *\/\r\n .workspace {\r\n display: grid;\r\n grid-template-columns: minmax(0, 1fr) 320px;\r\n gap: 14px;\r\n align-items: start;\r\n }\r\n\r\n .calculator-panel,\r\n .history-panel,\r\n .converter-panel,\r\n .settings-panel {\r\n border: 1px solid var(--border);\r\n background: var(--surface);\r\n border-radius: var(--radius-xl);\r\n box-shadow: var(--shadow);\r\n }\r\n\r\n .calculator-panel {\r\n overflow: hidden;\r\n }\r\n\r\n .calculator-body {\r\n padding: 14px;\r\n }\r\n\r\n .history-panel {\r\n padding: 14px;\r\n position: sticky;\r\n top: 14px;\r\n }\r\n\r\n \/* =========================================================\r\n 05. DISPLAY\r\n ========================================================== *\/\r\n .display {\r\n padding: 16px 16px 14px;\r\n background: var(--display);\r\n border-bottom: 1px solid var(--border);\r\n }\r\n\r\n .display-topline {\r\n display: flex;\r\n align-items: center;\r\n justify-content: space-between;\r\n gap: 10px;\r\n margin-bottom: 10px;\r\n }\r\n\r\n .indicators {\r\n display: flex;\r\n flex-wrap: wrap;\r\n gap: 6px;\r\n min-width: 0;\r\n }\r\n\r\n .indicator {\r\n display: inline-flex;\r\n align-items: center;\r\n min-height: 24px;\r\n padding: 0 8px;\r\n border: 1px solid var(--border);\r\n border-radius: 999px;\r\n color: var(--muted);\r\n font-size: 0.68rem;\r\n font-weight: 800;\r\n letter-spacing: 0.04em;\r\n }\r\n\r\n .indicator.is-active {\r\n border-color: color-mix(in srgb, var(--accent) 45%, var(--border));\r\n background: var(--accent-soft);\r\n color: var(--accent);\r\n }\r\n\r\n .display-tools {\r\n display: flex;\r\n gap: 7px;\r\n flex-shrink: 0;\r\n }\r\n\r\n .display-tool {\r\n min-height: 34px;\r\n padding: 0 10px;\r\n border: 1px solid var(--border);\r\n border-radius: 8px;\r\n background: transparent;\r\n color: var(--muted);\r\n cursor: pointer;\r\n font-size: 0.76rem;\r\n font-weight: 800;\r\n }\r\n\r\n .expression-input {\r\n width: 100%;\r\n min-height: 52px;\r\n padding: 6px 0 4px;\r\n border: 0;\r\n background: transparent;\r\n color: var(--text);\r\n font-size: clamp(1.12rem, 2.6vw, 1.58rem);\r\n font-weight: 560;\r\n letter-spacing: 0.005em;\r\n outline: none;\r\n font-variant-numeric: tabular-nums;\r\n }\r\n\r\n .result-row {\r\n display: flex;\r\n align-items: end;\r\n justify-content: space-between;\r\n gap: 12px;\r\n min-height: 62px;\r\n margin-top: 2px;\r\n }\r\n\r\n .result-output {\r\n min-width: 0;\r\n max-width: 100%;\r\n overflow-x: auto;\r\n overflow-y: hidden;\r\n color: var(--text);\r\n font-size: clamp(1.85rem, 5vw, 3rem);\r\n font-weight: 760;\r\n line-height: 1.08;\r\n letter-spacing: -0.035em;\r\n white-space: nowrap;\r\n font-variant-numeric: tabular-nums;\r\n scrollbar-width: thin;\r\n }\r\n\r\n .preview-output {\r\n flex: 0 0 auto;\r\n max-width: 46%;\r\n padding-bottom: 4px;\r\n overflow: hidden;\r\n color: var(--muted);\r\n font-size: 0.9rem;\r\n text-overflow: ellipsis;\r\n white-space: nowrap;\r\n font-variant-numeric: tabular-nums;\r\n }\r\n\r\n .message-line {\r\n min-height: 24px;\r\n margin-top: 6px;\r\n color: var(--muted);\r\n font-size: 0.8rem;\r\n }\r\n\r\n .message-line.is-error {\r\n color: var(--danger);\r\n }\r\n\r\n .message-line.is-success {\r\n color: var(--success);\r\n }\r\n\r\n \/* =========================================================\r\n 06. CALCULATOR CONTROLS\r\n ========================================================== *\/\r\n .control-strip {\r\n display: flex;\r\n align-items: center;\r\n justify-content: space-between;\r\n gap: 10px;\r\n flex-wrap: wrap;\r\n margin-bottom: 10px;\r\n }\r\n\r\n .control-strip-group {\r\n display: flex;\r\n align-items: center;\r\n flex-wrap: wrap;\r\n gap: 7px;\r\n }\r\n\r\n .tiny-button {\r\n min-height: 38px;\r\n min-width: 46px;\r\n padding: 0 11px;\r\n border: 1px solid var(--border);\r\n border-radius: 9px;\r\n background: var(--surface-2);\r\n color: var(--muted);\r\n cursor: pointer;\r\n font-size: 0.74rem;\r\n font-weight: 800;\r\n transition: background var(--transition), color var(--transition), transform var(--transition), border-color var(--transition);\r\n }\r\n\r\n .tiny-button[aria-pressed=\"true\"] {\r\n border-color: color-mix(in srgb, var(--accent) 40%, var(--border));\r\n background: var(--accent-soft);\r\n color: var(--accent);\r\n }\r\n\r\n .tiny-button.is-danger {\r\n color: var(--danger);\r\n }\r\n\r\n @media (hover: hover) and (pointer: fine) {\r\n .tiny-button:hover {\r\n background: var(--surface-3);\r\n color: var(--text);\r\n }\r\n }\r\n\r\n .keypad-layout {\r\n display: grid;\r\n grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.85fr);\r\n gap: 10px;\r\n }\r\n\r\n .scientific-grid,\r\n .numeric-grid {\r\n display: grid;\r\n gap: 8px;\r\n }\r\n\r\n .scientific-grid {\r\n grid-template-columns: repeat(6, minmax(0, 1fr));\r\n }\r\n\r\n .numeric-grid {\r\n grid-template-columns: repeat(4, minmax(0, 1fr));\r\n }\r\n\r\n .calc-key {\r\n position: relative;\r\n min-width: 0;\r\n min-height: 50px;\r\n padding: 8px 6px;\r\n border: 1px solid var(--border);\r\n border-radius: 11px;\r\n background: var(--surface-2);\r\n color: var(--text);\r\n cursor: pointer;\r\n font-size: 0.9rem;\r\n font-weight: 700;\r\n line-height: 1.15;\r\n transition: transform 120ms ease, background var(--transition), border-color var(--transition), color var(--transition);\r\n user-select: none;\r\n -webkit-tap-highlight-color: transparent;\r\n }\r\n\r\n .calc-key.key-number {\r\n background: var(--surface);\r\n font-size: 1rem;\r\n font-weight: 800;\r\n }\r\n\r\n .calc-key.key-operator {\r\n color: var(--accent);\r\n font-size: 1.05rem;\r\n }\r\n\r\n .calc-key.key-function {\r\n color: var(--muted);\r\n font-size: 0.82rem;\r\n }\r\n\r\n .calc-key.key-danger {\r\n color: var(--danger);\r\n background: var(--danger-soft);\r\n }\r\n\r\n .calc-key.key-equals {\r\n border-color: var(--accent);\r\n background: var(--accent);\r\n color: #0b1020;\r\n font-size: 1.08rem;\r\n font-weight: 900;\r\n }\r\n\r\n html[data-theme=\"light\"] .calc-key.key-equals {\r\n color: #ffffff;\r\n }\r\n\r\n .calc-key.key-shifted,\r\n .calc-key.is-flashed {\r\n border-color: color-mix(in srgb, var(--accent) 58%, var(--border));\r\n background: var(--accent-soft);\r\n color: var(--accent);\r\n }\r\n\r\n @media (hover: hover) and (pointer: fine) {\r\n .calc-key:hover {\r\n border-color: var(--border-strong);\r\n background: var(--surface-3);\r\n }\r\n\r\n .calc-key.key-equals:hover {\r\n border-color: var(--accent-strong);\r\n background: var(--accent-strong);\r\n }\r\n }\r\n\r\n .calc-key:active,\r\n .calc-key.is-flashed {\r\n transform: translateY(1px) scale(0.985);\r\n }\r\n\r\n \/* =========================================================\r\n 07. HISTORY\r\n ========================================================== *\/\r\n .panel-heading {\r\n display: flex;\r\n align-items: center;\r\n justify-content: space-between;\r\n gap: 10px;\r\n margin-bottom: 12px;\r\n }\r\n\r\n .panel-title {\r\n margin: 0;\r\n font-size: 0.98rem;\r\n letter-spacing: -0.01em;\r\n }\r\n\r\n .history-list {\r\n display: grid;\r\n gap: 8px;\r\n max-height: 580px;\r\n overflow-y: auto;\r\n padding-right: 2px;\r\n scrollbar-width: thin;\r\n }\r\n\r\n .history-empty {\r\n padding: 22px 12px;\r\n border: 1px dashed var(--border);\r\n border-radius: 12px;\r\n color: var(--muted);\r\n text-align: center;\r\n font-size: 0.84rem;\r\n }\r\n\r\n .history-item {\r\n position: relative;\r\n padding: 11px 38px 10px 11px;\r\n border: 1px solid var(--border);\r\n border-radius: 12px;\r\n background: var(--surface-2);\r\n }\r\n\r\n .history-expression,\r\n .history-result {\r\n width: 100%;\r\n padding: 0;\r\n border: 0;\r\n background: transparent;\r\n text-align: left;\r\n cursor: pointer;\r\n font-variant-numeric: tabular-nums;\r\n }\r\n\r\n .history-expression {\r\n overflow: hidden;\r\n color: var(--muted);\r\n font-size: 0.78rem;\r\n text-overflow: ellipsis;\r\n white-space: nowrap;\r\n }\r\n\r\n .history-result {\r\n margin-top: 3px;\r\n overflow: hidden;\r\n color: var(--text);\r\n font-size: 1rem;\r\n font-weight: 820;\r\n text-overflow: ellipsis;\r\n white-space: nowrap;\r\n }\r\n\r\n .history-time {\r\n display: block;\r\n margin-top: 5px;\r\n color: var(--subtle);\r\n font-size: 0.68rem;\r\n }\r\n\r\n .history-delete {\r\n position: absolute;\r\n top: 8px;\r\n right: 8px;\r\n width: 28px;\r\n height: 28px;\r\n border-radius: 8px;\r\n background: transparent;\r\n color: var(--subtle);\r\n cursor: pointer;\r\n }\r\n\r\n \/* =========================================================\r\n 08. CONVERTER\r\n ========================================================== *\/\r\n .converter-panel {\r\n padding: 18px;\r\n }\r\n\r\n .converter-head {\r\n display: flex;\r\n align-items: start;\r\n justify-content: space-between;\r\n gap: 12px;\r\n margin-bottom: 18px;\r\n }\r\n\r\n .converter-title {\r\n margin: 0 0 3px;\r\n font-size: 1.12rem;\r\n }\r\n\r\n .converter-subtitle {\r\n margin: 0;\r\n color: var(--muted);\r\n font-size: 0.82rem;\r\n }\r\n\r\n .converter-grid {\r\n display: grid;\r\n grid-template-columns: repeat(2, minmax(0, 1fr));\r\n gap: 14px;\r\n }\r\n\r\n .converter-card {\r\n padding: 14px;\r\n border: 1px solid var(--border);\r\n border-radius: var(--radius-lg);\r\n background: var(--surface-2);\r\n }\r\n\r\n .field-label {\r\n display: block;\r\n margin-bottom: 6px;\r\n color: var(--muted);\r\n font-size: 0.74rem;\r\n font-weight: 780;\r\n letter-spacing: 0.03em;\r\n text-transform: uppercase;\r\n }\r\n\r\n .field-control {\r\n width: 100%;\r\n min-height: 48px;\r\n padding: 0 12px;\r\n border: 1px solid var(--border);\r\n border-radius: 10px;\r\n background: var(--surface);\r\n color: var(--text);\r\n outline: none;\r\n }\r\n\r\n .field-stack {\r\n display: grid;\r\n gap: 12px;\r\n }\r\n\r\n .converter-result {\r\n display: flex;\r\n align-items: end;\r\n min-height: 48px;\r\n padding: 8px 12px;\r\n border: 1px solid var(--border);\r\n border-radius: 10px;\r\n background: var(--display);\r\n color: var(--text);\r\n font-size: 1.1rem;\r\n font-weight: 820;\r\n font-variant-numeric: tabular-nums;\r\n overflow-wrap: anywhere;\r\n }\r\n\r\n \/* =========================================================\r\n 09. SETTINGS DIALOG\r\n ========================================================== *\/\r\n .settings-backdrop {\r\n position: fixed;\r\n inset: 0;\r\n z-index: 40;\r\n display: grid;\r\n place-items: center;\r\n padding: 18px;\r\n background: rgba(3, 7, 12, 0.66);\r\n }\r\n\r\n .settings-panel {\r\n width: min(100%, 520px);\r\n max-height: min(720px, calc(100vh - 36px));\r\n overflow-y: auto;\r\n padding: 18px;\r\n }\r\n\r\n .settings-list {\r\n display: grid;\r\n gap: 14px;\r\n }\r\n\r\n .setting-row {\r\n display: grid;\r\n grid-template-columns: minmax(0, 1fr) minmax(160px, 0.62fr);\r\n gap: 14px;\r\n align-items: center;\r\n }\r\n\r\n .setting-copy strong {\r\n display: block;\r\n font-size: 0.88rem;\r\n }\r\n\r\n .setting-copy span {\r\n display: block;\r\n margin-top: 2px;\r\n color: var(--muted);\r\n font-size: 0.76rem;\r\n }\r\n\r\n .settings-footer {\r\n display: flex;\r\n justify-content: flex-end;\r\n gap: 8px;\r\n margin-top: 18px;\r\n }\r\n\r\n .shortcut-list {\r\n display: grid;\r\n grid-template-columns: repeat(2, minmax(0, 1fr));\r\n gap: 7px 12px;\r\n padding: 12px;\r\n border: 1px solid var(--border);\r\n border-radius: 12px;\r\n background: var(--surface-2);\r\n }\r\n\r\n .shortcut-item {\r\n display: flex;\r\n justify-content: space-between;\r\n gap: 10px;\r\n color: var(--muted);\r\n font-size: 0.76rem;\r\n }\r\n\r\n .shortcut-item kbd {\r\n min-width: 32px;\r\n padding: 2px 7px;\r\n border: 1px solid var(--border-strong);\r\n border-radius: 6px;\r\n background: var(--surface);\r\n color: var(--text);\r\n text-align: center;\r\n font: inherit;\r\n font-weight: 780;\r\n }\r\n\r\n \/* =========================================================\r\n 10. MOBILE HISTORY DRAWER\r\n ========================================================== *\/\r\n .mobile-history-toggle {\r\n display: none;\r\n }\r\n\r\n .mobile-history-backdrop {\r\n display: none;\r\n }\r\n\r\n \/* =========================================================\r\n 11. RESPONSIVE\r\n ========================================================== *\/\r\n @media (max-width: 1080px) {\r\n .workspace {\r\n grid-template-columns: minmax(0, 1fr) 286px;\r\n }\r\n\r\n .keypad-layout {\r\n grid-template-columns: 1fr;\r\n }\r\n\r\n .scientific-grid {\r\n grid-template-columns: repeat(6, minmax(0, 1fr));\r\n }\r\n }\r\n\r\n @media (max-width: 820px) {\r\n .app-shell {\r\n width: min(100% - 16px, var(--max-width));\r\n margin-top: 8px;\r\n }\r\n\r\n .app-header {\r\n align-items: flex-start;\r\n }\r\n\r\n .workspace {\r\n grid-template-columns: 1fr;\r\n }\r\n\r\n .history-panel {\r\n position: fixed;\r\n top: 0;\r\n right: 0;\r\n z-index: 31;\r\n width: min(88vw, 360px);\r\n height: 100%;\r\n border-radius: 20px 0 0 20px;\r\n transform: translateX(104%);\r\n transition: transform var(--transition);\r\n }\r\n\r\n .history-panel.is-open {\r\n transform: translateX(0);\r\n }\r\n\r\n .mobile-history-toggle {\r\n display: inline-grid;\r\n }\r\n\r\n .mobile-history-backdrop {\r\n position: fixed;\r\n inset: 0;\r\n z-index: 30;\r\n display: block;\r\n background: rgba(3, 7, 12, 0.56);\r\n }\r\n\r\n .history-list {\r\n max-height: calc(100vh - 94px);\r\n }\r\n }\r\n\r\n @media (max-width: 640px) {\r\n .app-header {\r\n gap: 10px;\r\n }\r\n\r\n .brand-kicker {\r\n display: none;\r\n }\r\n\r\n .header-actions {\r\n gap: 6px;\r\n }\r\n\r\n .mode-switch {\r\n order: 3;\r\n width: 100%;\r\n }\r\n\r\n .mode-button {\r\n flex: 1 1 0;\r\n }\r\n\r\n .calculator-body,\r\n .display {\r\n padding-left: 10px;\r\n padding-right: 10px;\r\n }\r\n\r\n .display-topline {\r\n align-items: flex-start;\r\n }\r\n\r\n .preview-output {\r\n max-width: 42%;\r\n }\r\n\r\n .scientific-grid {\r\n grid-template-columns: repeat(4, minmax(0, 1fr));\r\n }\r\n\r\n .calc-key {\r\n min-height: 48px;\r\n }\r\n\r\n .converter-grid,\r\n .setting-row {\r\n grid-template-columns: 1fr;\r\n }\r\n\r\n .shortcut-list {\r\n grid-template-columns: 1fr;\r\n }\r\n }\r\n\r\n @media (max-width: 390px) {\r\n .app-shell {\r\n width: min(100% - 10px, var(--max-width));\r\n }\r\n\r\n .brand-title {\r\n font-size: 1.05rem;\r\n }\r\n\r\n .icon-button {\r\n width: 42px;\r\n }\r\n\r\n .scientific-grid {\r\n grid-template-columns: repeat(3, minmax(0, 1fr));\r\n }\r\n\r\n .numeric-grid {\r\n gap: 7px;\r\n }\r\n\r\n .calc-key {\r\n padding-inline: 4px;\r\n }\r\n }\r\n\r\n @media (prefers-reduced-motion: reduce) {\r\n *,\r\n *::before,\r\n *::after {\r\n scroll-behavior: auto !important;\r\n transition-duration: 0.01ms !important;\r\n animation-duration: 0.01ms !important;\r\n }\r\n }\r\n <\/style>\r\n<\/head>\r\n<body>\r\n <main class=\"app-shell\" id=\"appRoot\">\r\n \r\n <header class=\"app-header\">\r\n <div class=\"brand-group\">\r\n <p class=\"brand-kicker\">Precision workspace<\/p>\r\n <h1 class=\"brand-title\">NOVA Scientific<\/h1>\r\n <\/div>\r\n\r\n <div class=\"header-actions\">\r\n <div class=\"mode-switch\" aria-label=\"Application mode\">\r\n <button class=\"mode-button\" id=\"scientificModeButton\" type=\"button\" aria-pressed=\"true\">Scientific<\/button>\r\n <button class=\"mode-button\" id=\"converterModeButton\" type=\"button\" aria-pressed=\"false\">Converter<\/button>\r\n <\/div>\r\n\r\n <button class=\"icon-button mobile-history-toggle\" id=\"mobileHistoryButton\" type=\"button\" aria-label=\"Open calculation history\" title=\"History\">\u2315<\/button>\r\n <button class=\"icon-button\" id=\"themeButton\" type=\"button\" aria-label=\"Toggle color theme\" title=\"Toggle theme\">\u25d0<\/button>\r\n <button class=\"icon-button\" id=\"settingsButton\" type=\"button\" aria-label=\"Open settings\" title=\"Settings\">\u2699<\/button>\r\n <\/div>\r\n <\/header>\r\n\r\n \r\n <section class=\"workspace\" id=\"scientificWorkspace\" aria-label=\"Scientific calculator workspace\">\r\n <section class=\"calculator-panel\" aria-label=\"Scientific calculator\">\r\n \r\n <div class=\"display\">\r\n <div class=\"display-topline\">\r\n <div class=\"indicators\" aria-label=\"Calculator status\">\r\n <span class=\"indicator is-active\" id=\"angleIndicator\">DEG<\/span>\r\n <span class=\"indicator\" id=\"memoryIndicator\">M<\/span>\r\n <span class=\"indicator\" id=\"shiftIndicator\">2nd<\/span>\r\n <span class=\"indicator is-active\" id=\"formatIndicator\">NORMAL<\/span>\r\n <\/div>\r\n\r\n <div class=\"display-tools\">\r\n <button class=\"display-tool\" id=\"fractionButton\" type=\"button\" title=\"Convert result to fraction\">a\/b<\/button>\r\n <button class=\"display-tool\" id=\"copyButton\" type=\"button\" title=\"Copy result\">Copy<\/button>\r\n <\/div>\r\n <\/div>\r\n\r\n <label for=\"expressionInput\" class=\"field-label\" style=\"position:absolute;left:-9999px;\">Expression<\/label>\r\n <input\r\n class=\"expression-input\"\r\n id=\"expressionInput\"\r\n type=\"text\"\r\n inputmode=\"text\"\r\n autocomplete=\"off\"\r\n autocapitalize=\"off\"\r\n spellcheck=\"false\"\r\n aria-describedby=\"messageLine\"\r\n placeholder=\"Enter an expression\u2026\"\r\n >\r\n\r\n <div class=\"result-row\">\r\n <output class=\"result-output\" id=\"resultOutput\" aria-live=\"polite\">0<\/output>\r\n <div class=\"preview-output\" id=\"previewOutput\" aria-live=\"off\"><\/div>\r\n <\/div>\r\n\r\n <div class=\"message-line\" id=\"messageLine\" aria-live=\"polite\"><\/div>\r\n <\/div>\r\n\r\n \r\n <div class=\"calculator-body\">\r\n <div class=\"control-strip\">\r\n <div class=\"control-strip-group\" aria-label=\"Angle mode\">\r\n <button class=\"tiny-button\" type=\"button\" data-angle=\"DEG\" aria-pressed=\"true\">DEG<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-angle=\"RAD\" aria-pressed=\"false\">RAD<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-angle=\"GRAD\" aria-pressed=\"false\">GRAD<\/button>\r\n <\/div>\r\n\r\n <div class=\"control-strip-group\" aria-label=\"Memory controls\">\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-clear\">MC<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-recall\">MR<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-add\">M+<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-subtract\">M\u2212<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-store\">MS<\/button>\r\n <\/div>\r\n <\/div>\r\n\r\n <div class=\"keypad-layout\">\r\n \r\n <div class=\"scientific-grid\" id=\"scientificGrid\" aria-label=\"Scientific functions\">\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"shift\" id=\"shiftButton\">2nd<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"(\">(<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\")\">)<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"smart-parenthesis\">( )<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"pi\">\u03c0<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"e\">e<\/button>\r\n\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"sin\" data-shift-label=\"sin\u207b\u00b9\" data-normal-insert=\"sin(\" data-shift-insert=\"asin(\" data-insert=\"sin(\">sin<\/button>\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"cos\" data-shift-label=\"cos\u207b\u00b9\" data-normal-insert=\"cos(\" data-shift-insert=\"acos(\" data-insert=\"cos(\">cos<\/button>\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"tan\" data-shift-label=\"tan\u207b\u00b9\" data-normal-insert=\"tan(\" data-shift-insert=\"atan(\" data-insert=\"tan(\">tan<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"sinh(\">sinh<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"cosh(\">cosh<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"tanh(\">tanh<\/button>\r\n\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"x\u00b2\" data-shift-label=\"\u221ax\" data-normal-action=\"square\" data-shift-insert=\"sqrt(\" data-action=\"square\">x\u00b2<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"cube\">x\u00b3<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"^\">x\u02b8<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"sqrt(\">\u221ax<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"cbrt(\">\u221bx<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"root(\">\u02b8\u221ax<\/button>\r\n\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"10\u02e3\" data-shift-label=\"log\" data-normal-insert=\"10^(\" data-shift-insert=\"log(\" data-insert=\"10^(\">10\u02e3<\/button>\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"e\u02e3\" data-shift-label=\"ln\" data-normal-insert=\"e^(\" data-shift-insert=\"ln(\" data-insert=\"e^(\">e\u02e3<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"2^(\">2\u02e3<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"log(\">log<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"ln(\">ln<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"log2(\">log\u2082<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"abs(\">|x|<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"!\">x!<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"reciprocal\">1\/x<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"floor(\">floor<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"ceil(\">ceil<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"round(\">round<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"ncr(\">nCr<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"npr(\">nPr<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"gcd(\">gcd<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"lcm(\">lcm<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"mod(\">mod<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"random\">RAND<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"min(\">min<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"max(\">max<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"trunc(\">trunc<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"sign(\">sign<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"phi\">\u03c6<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"E\">EXP<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"logb(\">log\u1d66<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"randbetween(\">RND(a,b)<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"atanh(\">atanh<\/button>\r\n <\/div>\r\n\r\n \r\n <div class=\"numeric-grid\" id=\"numericGrid\" aria-label=\"Basic calculator keypad\">\r\n <button class=\"calc-key key-danger\" type=\"button\" data-action=\"clear\">AC<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"backspace\">\u232b<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"%\">%<\/button>\r\n <button class=\"calc-key key-operator\" type=\"button\" data-insert=\"\u00f7\">\u00f7<\/button>\r\n\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"7\">7<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"8\">8<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"9\">9<\/button>\r\n <button class=\"calc-key key-operator\" type=\"button\" data-insert=\"\u00d7\">\u00d7<\/button>\r\n\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"4\">4<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"5\">5<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"6\">6<\/button>\r\n <button class=\"calc-key key-operator\" type=\"button\" data-insert=\"-\">\u2212<\/button>\r\n\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"1\">1<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"2\">2<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"3\">3<\/button>\r\n <button class=\"calc-key key-operator\" type=\"button\" data-insert=\"+\">+<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"toggle-sign\">\u00b1<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"0\">0<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\".\">.<\/button>\r\n <button class=\"calc-key key-equals\" type=\"button\" data-action=\"evaluate\">=<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"ans\">ANS<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\",\">,<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"asinh(\">asinh<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"acosh(\">acosh<\/button>\r\n <\/div>\r\n <\/div>\r\n <\/div>\r\n <\/section>\r\n\r\n \r\n <aside class=\"history-panel\" id=\"historyPanel\" aria-label=\"Calculation history\">\r\n <div class=\"panel-heading\">\r\n <h2 class=\"panel-title\">History<\/h2>\r\n <button class=\"soft-button\" id=\"clearHistoryButton\" type=\"button\">Clear<\/button>\r\n <\/div>\r\n <div class=\"history-list\" id=\"historyList\"><\/div>\r\n <\/aside>\r\n <\/section>\r\n\r\n \r\n <section class=\"converter-panel\" id=\"converterWorkspace\" aria-label=\"Unit converter\" hidden>\r\n <div class=\"converter-head\">\r\n <div>\r\n <h2 class=\"converter-title\">Unit converter<\/h2>\r\n <p class=\"converter-subtitle\">Offline conversions for common scientific and everyday units.<\/p>\r\n <\/div>\r\n <span class=\"indicator is-active\">LOCAL<\/span>\r\n <\/div>\r\n\r\n <div class=\"converter-grid\">\r\n <div class=\"converter-card field-stack\">\r\n <div>\r\n <label class=\"field-label\" for=\"converterCategory\">Category<\/label>\r\n <select class=\"field-control\" id=\"converterCategory\"><\/select>\r\n <\/div>\r\n <div>\r\n <label class=\"field-label\" for=\"converterValue\">Value<\/label>\r\n <input class=\"field-control\" id=\"converterValue\" type=\"number\" inputmode=\"decimal\" step=\"any\" value=\"1\">\r\n <\/div>\r\n <\/div>\r\n\r\n <div class=\"converter-card field-stack\">\r\n <div>\r\n <label class=\"field-label\" for=\"converterFrom\">From<\/label>\r\n <select class=\"field-control\" id=\"converterFrom\"><\/select>\r\n <\/div>\r\n <div>\r\n <label class=\"field-label\" for=\"converterTo\">To<\/label>\r\n <select class=\"field-control\" id=\"converterTo\"><\/select>\r\n <\/div>\r\n <\/div>\r\n\r\n <div class=\"converter-card field-stack\">\r\n <div>\r\n <span class=\"field-label\">Converted result<\/span>\r\n <output class=\"converter-result\" id=\"converterResult\" aria-live=\"polite\">1<\/output>\r\n <\/div>\r\n <button class=\"soft-button\" id=\"swapUnitsButton\" type=\"button\">Swap units<\/button>\r\n <\/div>\r\n\r\n <div class=\"converter-card field-stack\">\r\n <div>\r\n <span class=\"field-label\">Formula<\/span>\r\n <div class=\"converter-result\" id=\"converterFormula\" style=\"font-size:0.88rem;font-weight:650;color:var(--muted);\">Direct scale conversion<\/div>\r\n <\/div>\r\n <\/div>\r\n <\/div>\r\n <\/section>\r\n <\/main>\r\n\r\n \r\n <button class=\"mobile-history-backdrop\" id=\"mobileHistoryBackdrop\" type=\"button\" aria-label=\"Close history\" hidden><\/button>\r\n\r\n \r\n <div class=\"settings-backdrop\" id=\"settingsBackdrop\" hidden>\r\n <section class=\"settings-panel\" role=\"dialog\" aria-modal=\"true\" aria-labelledby=\"settingsTitle\">\r\n <div class=\"panel-heading\">\r\n <h2 class=\"panel-title\" id=\"settingsTitle\">Calculator settings<\/h2>\r\n <button class=\"icon-button\" id=\"closeSettingsButton\" type=\"button\" aria-label=\"Close settings\">\u00d7<\/button>\r\n <\/div>\r\n\r\n <div class=\"settings-list\">\r\n <div class=\"setting-row\">\r\n <div class=\"setting-copy\">\r\n <strong>Theme<\/strong>\r\n <span>Choose light or dark appearance.<\/span>\r\n <\/div>\r\n <select class=\"field-control\" id=\"themeSelect\">\r\n <option value=\"dark\">Dark<\/option>\r\n <option value=\"light\">Light<\/option>\r\n <\/select>\r\n <\/div>\r\n\r\n <div class=\"setting-row\">\r\n <div class=\"setting-copy\">\r\n <strong>Number format<\/strong>\r\n <span>Normal, scientific, or engineering notation.<\/span>\r\n <\/div>\r\n <select class=\"field-control\" id=\"formatSelect\">\r\n <option value=\"normal\">Normal<\/option>\r\n <option value=\"scientific\">Scientific<\/option>\r\n <option value=\"engineering\">Engineering<\/option>\r\n <\/select>\r\n <\/div>\r\n\r\n <div class=\"setting-row\">\r\n <div class=\"setting-copy\">\r\n <strong>Precision<\/strong>\r\n <span>Display precision only; internal calculations keep full floating-point precision.<\/span>\r\n <\/div>\r\n <select class=\"field-control\" id=\"precisionSelect\">\r\n <option value=\"auto\">Auto<\/option>\r\n <option value=\"4\">4 decimals<\/option>\r\n <option value=\"6\">6 decimals<\/option>\r\n <option value=\"8\">8 decimals<\/option>\r\n <option value=\"10\">10 decimals<\/option>\r\n <option value=\"12\">12 decimals<\/option>\r\n <\/select>\r\n <\/div>\r\n\r\n <div class=\"setting-row\">\r\n <div class=\"setting-copy\">\r\n <strong>History persistence<\/strong>\r\n <span>Keep recent calculations after closing the browser.<\/span>\r\n <\/div>\r\n <select class=\"field-control\" id=\"historyPersistenceSelect\">\r\n <option value=\"on\">On<\/option>\r\n <option value=\"off\">Off<\/option>\r\n <\/select>\r\n <\/div>\r\n\r\n <div>\r\n <span class=\"field-label\">Keyboard shortcuts<\/span>\r\n <div class=\"shortcut-list\">\r\n <div class=\"shortcut-item\"><span>Calculate<\/span><kbd>Enter<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Clear<\/span><kbd>Esc<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Delete<\/span><kbd>\u232b<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Power<\/span><kbd>^<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Multiply<\/span><kbd>*<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Divide<\/span><kbd>\/<\/kbd><\/div>\r\n <\/div>\r\n <\/div>\r\n <\/div>\r\n\r\n <div class=\"settings-footer\">\r\n <button class=\"soft-button\" id=\"resetSettingsButton\" type=\"button\">Reset settings<\/button>\r\n <button class=\"soft-button\" id=\"doneSettingsButton\" type=\"button\">Done<\/button>\r\n <\/div>\r\n <\/section>\r\n <\/div>\r\n\r\n <script>\r\n \"use strict\";\r\n\r\n \/* =========================================================\r\n 01. CONSTANTS & APPLICATION STATE\r\n ========================================================== *\/\r\n const STORAGE_KEYS = {\r\n theme: \"nova.theme\",\r\n angle: \"nova.angle\",\r\n precision: \"nova.precision\",\r\n format: \"nova.format\",\r\n history: \"nova.history\",\r\n historyPersistence: \"nova.historyPersistence\"\r\n };\r\n\r\n const MAX_HISTORY = 60;\r\n const MAX_FACTORIAL = 170;\r\n const GOLDEN_RATIO = (1 + Math.sqrt(5)) \/ 2;\r\n\r\n const state = {\r\n expression: \"\",\r\n result: 0,\r\n previousAnswer: 0,\r\n memory: 0,\r\n angleMode: \"DEG\",\r\n secondMode: false,\r\n theme: \"dark\",\r\n numberFormat: \"normal\",\r\n precision: \"auto\",\r\n historyPersistence: true,\r\n history: [],\r\n justEvaluated: false,\r\n lastEvaluation: null,\r\n currentMode: \"scientific\"\r\n };\r\n\r\n \/* =========================================================\r\n 02. DOM CACHE\r\n ========================================================== *\/\r\n const dom = {\r\n html: document.documentElement,\r\n expressionInput: document.getElementById(\"expressionInput\"),\r\n resultOutput: document.getElementById(\"resultOutput\"),\r\n previewOutput: document.getElementById(\"previewOutput\"),\r\n messageLine: document.getElementById(\"messageLine\"),\r\n angleIndicator: document.getElementById(\"angleIndicator\"),\r\n memoryIndicator: document.getElementById(\"memoryIndicator\"),\r\n shiftIndicator: document.getElementById(\"shiftIndicator\"),\r\n formatIndicator: document.getElementById(\"formatIndicator\"),\r\n scientificWorkspace: document.getElementById(\"scientificWorkspace\"),\r\n converterWorkspace: document.getElementById(\"converterWorkspace\"),\r\n scientificModeButton: document.getElementById(\"scientificModeButton\"),\r\n converterModeButton: document.getElementById(\"converterModeButton\"),\r\n themeButton: document.getElementById(\"themeButton\"),\r\n settingsButton: document.getElementById(\"settingsButton\"),\r\n copyButton: document.getElementById(\"copyButton\"),\r\n fractionButton: document.getElementById(\"fractionButton\"),\r\n shiftButton: document.getElementById(\"shiftButton\"),\r\n historyList: document.getElementById(\"historyList\"),\r\n historyPanel: document.getElementById(\"historyPanel\"),\r\n clearHistoryButton: document.getElementById(\"clearHistoryButton\"),\r\n mobileHistoryButton: document.getElementById(\"mobileHistoryButton\"),\r\n mobileHistoryBackdrop: document.getElementById(\"mobileHistoryBackdrop\"),\r\n settingsBackdrop: document.getElementById(\"settingsBackdrop\"),\r\n closeSettingsButton: document.getElementById(\"closeSettingsButton\"),\r\n doneSettingsButton: document.getElementById(\"doneSettingsButton\"),\r\n resetSettingsButton: document.getElementById(\"resetSettingsButton\"),\r\n themeSelect: document.getElementById(\"themeSelect\"),\r\n formatSelect: document.getElementById(\"formatSelect\"),\r\n precisionSelect: document.getElementById(\"precisionSelect\"),\r\n historyPersistenceSelect: document.getElementById(\"historyPersistenceSelect\"),\r\n converterCategory: document.getElementById(\"converterCategory\"),\r\n converterValue: document.getElementById(\"converterValue\"),\r\n converterFrom: document.getElementById(\"converterFrom\"),\r\n converterTo: document.getElementById(\"converterTo\"),\r\n converterResult: document.getElementById(\"converterResult\"),\r\n converterFormula: document.getElementById(\"converterFormula\"),\r\n swapUnitsButton: document.getElementById(\"swapUnitsButton\")\r\n };\r\n\r\n \/* =========================================================\r\n 03. UTILITY HELPERS\r\n ========================================================== *\/\r\n function clamp(value, min, max) {\r\n return Math.min(Math.max(value, min), max);\r\n }\r\n\r\n function nearlyInteger(value) {\r\n return Math.abs(value - Math.round(value)) < 1e-12;\r\n }\r\n\r\n function isFiniteNumber(value) {\r\n return typeof value === \"number\" && Number.isFinite(value);\r\n }\r\n\r\n function safeStorageGet(key) {\r\n try {\r\n return localStorage.getItem(key);\r\n } catch {\r\n return null;\r\n }\r\n }\r\n\r\n function safeStorageSet(key, value) {\r\n try {\r\n localStorage.setItem(key, value);\r\n return true;\r\n } catch {\r\n return false;\r\n }\r\n }\r\n\r\n function safeStorageRemove(key) {\r\n try {\r\n localStorage.removeItem(key);\r\n } catch {\r\n \/\/ Persistence is optional; silently continue.\r\n }\r\n }\r\n\r\n function normalizeNegativeZero(value) {\r\n return Object.is(value, -0) ? 0 : value;\r\n }\r\n\r\n function roundFloatingNoise(value) {\r\n if (!isFiniteNumber(value)) return value;\r\n if (value === 0) return 0;\r\n const magnitude = Math.abs(value);\r\n if (magnitude >= 1e15 || magnitude < 1e-12) return value;\r\n return Number.parseFloat(value.toPrecision(15));\r\n }\r\n\r\n function showMessage(message = \"\", type = \"neutral\") {\r\n dom.messageLine.textContent = message;\r\n dom.messageLine.classList.toggle(\"is-error\", type === \"error\");\r\n dom.messageLine.classList.toggle(\"is-success\", type === \"success\");\r\n }\r\n\r\n function clearMessage() {\r\n showMessage(\"\");\r\n }\r\n\r\n \/* =========================================================\r\n 04. MATHEMATICAL DOMAIN HELPERS\r\n ========================================================== *\/\r\n function toRadians(value) {\r\n if (state.angleMode === \"DEG\") return value * Math.PI \/ 180;\r\n if (state.angleMode === \"GRAD\") return value * Math.PI \/ 200;\r\n return value;\r\n }\r\n\r\n function fromRadians(value) {\r\n if (state.angleMode === \"DEG\") return value * 180 \/ Math.PI;\r\n if (state.angleMode === \"GRAD\") return value * 200 \/ Math.PI;\r\n return value;\r\n }\r\n\r\n function factorial(value) {\r\n if (!nearlyInteger(value) || value < 0) {\r\n throw new CalcError(\"Factorial requires a non-negative integer\");\r\n }\r\n if (value > MAX_FACTORIAL) {\r\n throw new CalcError(\"Factorial is too large for this calculator\");\r\n }\r\n let result = 1;\r\n for (let i = 2; i <= value; i += 1) result *= i;\r\n return result;\r\n }\r\n\r\n function integerGcd(a, b) {\r\n if (!nearlyInteger(a) || !nearlyInteger(b)) {\r\n throw new CalcError(\"gcd requires integer arguments\");\r\n }\r\n a = Math.abs(Math.trunc(a));\r\n b = Math.abs(Math.trunc(b));\r\n while (b !== 0) {\r\n [a, b] = [b, a % b];\r\n }\r\n return a;\r\n }\r\n\r\n function integerLcm(a, b) {\r\n if (!nearlyInteger(a) || !nearlyInteger(b)) {\r\n throw new CalcError(\"lcm requires integer arguments\");\r\n }\r\n if (a === 0 || b === 0) return 0;\r\n return Math.abs((a \/ integerGcd(a, b)) * b);\r\n }\r\n\r\n function combination(n, r) {\r\n if (!nearlyInteger(n) || !nearlyInteger(r) || n < 0 || r < 0 || r > n) {\r\n throw new CalcError(\"nCr requires integers with 0 \u2264 r \u2264 n\");\r\n }\r\n r = Math.min(r, n - r);\r\n let result = 1;\r\n for (let i = 1; i <= r; i += 1) {\r\n result = result * (n - r + i) \/ i;\r\n }\r\n return result;\r\n }\r\n\r\n function permutation(n, r) {\r\n if (!nearlyInteger(n) || !nearlyInteger(r) || n < 0 || r < 0 || r > n) {\r\n throw new CalcError(\"nPr requires integers with 0 \u2264 r \u2264 n\");\r\n }\r\n let result = 1;\r\n for (let i = 0; i < r; i += 1) result *= (n - i);\r\n return result;\r\n }\r\n\r\n \/* =========================================================\r\n 05. CALCULATOR ERROR TYPE\r\n ========================================================== *\/\r\n class CalcError extends Error {\r\n constructor(message) {\r\n super(message);\r\n this.name = \"CalcError\";\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 06. TOKENIZER\r\n ========================================================== *\/\r\n const FUNCTION_NAMES = new Set([\r\n \"sin\", \"cos\", \"tan\", \"asin\", \"acos\", \"atan\",\r\n \"sinh\", \"cosh\", \"tanh\", \"asinh\", \"acosh\", \"atanh\",\r\n \"log\", \"ln\", \"log2\", \"logb\", \"sqrt\", \"cbrt\", \"root\",\r\n \"abs\", \"floor\", \"ceil\", \"round\", \"trunc\", \"sign\",\r\n \"min\", \"max\", \"gcd\", \"lcm\", \"ncr\", \"npr\", \"mod\",\r\n \"randbetween\"\r\n ]);\r\n\r\n const CONSTANT_NAMES = new Set([\"pi\", \"e\", \"phi\", \"ans\"]);\r\n\r\n function normalizeExpressionSource(source) {\r\n return source\r\n .replace(\/\u00d7\/g, \"*\")\r\n .replace(\/\u00f7\/g, \"\/\")\r\n .replace(\/[\u2212\u2013\u2014]\/g, \"-\")\r\n .replace(\/\u03c0\/g, \"pi\")\r\n .replace(\/\u03c6\/g, \"phi\")\r\n .replace(\/\u221a\/g, \"sqrt\")\r\n .trim();\r\n }\r\n\r\n function tokenize(source) {\r\n const input = normalizeExpressionSource(source);\r\n const tokens = [];\r\n let index = 0;\r\n\r\n while (index < input.length) {\r\n const char = input[index];\r\n\r\n if (\/\\s\/.test(char)) {\r\n index += 1;\r\n continue;\r\n }\r\n\r\n if (\/\\d|\\.\/.test(char)) {\r\n const start = index;\r\n let sawDot = false;\r\n\r\n if (char === \".\") sawDot = true;\r\n index += 1;\r\n\r\n while (index < input.length) {\r\n const next = input[index];\r\n if (\/\\d\/.test(next)) {\r\n index += 1;\r\n continue;\r\n }\r\n if (next === \".\" && !sawDot) {\r\n sawDot = true;\r\n index += 1;\r\n continue;\r\n }\r\n break;\r\n }\r\n\r\n if (input[index] === \"e\" || input[index] === \"E\") {\r\n let exponentIndex = index + 1;\r\n if (input[exponentIndex] === \"+\" || input[exponentIndex] === \"-\") exponentIndex += 1;\r\n const digitsStart = exponentIndex;\r\n while (\/\\d\/.test(input[exponentIndex] || \"\")) exponentIndex += 1;\r\n if (exponentIndex > digitsStart) index = exponentIndex;\r\n }\r\n\r\n const raw = input.slice(start, index);\r\n if (!\/^(?:\\d+\\.?\\d*|\\.\\d+)(?:[eE][+-]?\\d+)?$\/.test(raw)) {\r\n throw new CalcError(\"Invalid number format\");\r\n }\r\n tokens.push({ type: \"number\", value: Number(raw), raw });\r\n continue;\r\n }\r\n\r\n if (\/[A-Za-z]\/.test(char)) {\r\n const start = index;\r\n index += 1;\r\n while (\/[A-Za-z0-9_]\/.test(input[index] || \"\")) index += 1;\r\n const name = input.slice(start, index).toLowerCase();\r\n tokens.push({ type: \"identifier\", value: name });\r\n continue;\r\n }\r\n\r\n if (\"+-*\/^!%,()\".includes(char)) {\r\n if (char === \"(\") tokens.push({ type: \"lparen\", value: char });\r\n else if (char === \")\") tokens.push({ type: \"rparen\", value: char });\r\n else if (char === \",\") tokens.push({ type: \"comma\", value: char });\r\n else tokens.push({ type: \"operator\", value: char });\r\n index += 1;\r\n continue;\r\n }\r\n\r\n throw new CalcError(`Unsupported symbol: ${char}`);\r\n }\r\n\r\n return insertImplicitMultiplication(tokens);\r\n }\r\n\r\n function canEndImplicitMultiplication(token) {\r\n if (!token) return false;\r\n return token.type === \"number\" ||\r\n token.type === \"rparen\" ||\r\n (token.type === \"identifier\" && CONSTANT_NAMES.has(token.value)) ||\r\n (token.type === \"operator\" && (token.value === \"!\" || token.value === \"%\"));\r\n }\r\n\r\n function canStartImplicitMultiplication(token) {\r\n if (!token) return false;\r\n if (token.type === \"number\" || token.type === \"lparen\") return true;\r\n if (token.type === \"identifier\") return true;\r\n return false;\r\n }\r\n\r\n function insertImplicitMultiplication(tokens) {\r\n const output = [];\r\n\r\n for (let i = 0; i < tokens.length; i += 1) {\r\n const current = tokens[i];\r\n const previous = output[output.length - 1];\r\n\r\n const previousIsFunction = previous?.type === \"identifier\" && FUNCTION_NAMES.has(previous.value);\r\n const currentIsLParen = current.type === \"lparen\";\r\n\r\n if (\r\n previous &&\r\n canEndImplicitMultiplication(previous) &&\r\n canStartImplicitMultiplication(current) &&\r\n !(previousIsFunction && currentIsLParen)\r\n ) {\r\n output.push({ type: \"operator\", value: \"*\", implicit: true });\r\n }\r\n\r\n output.push(current);\r\n }\r\n\r\n return output;\r\n }\r\n\r\n \/* =========================================================\r\n 07. RECURSIVE-DESCENT EXPRESSION PARSER\r\n ========================================================== *\/\r\n class Parser {\r\n constructor(tokens) {\r\n this.tokens = tokens;\r\n this.position = 0;\r\n }\r\n\r\n peek(offset = 0) {\r\n return this.tokens[this.position + offset] || null;\r\n }\r\n\r\n consume() {\r\n return this.tokens[this.position++] || null;\r\n }\r\n\r\n match(type, value = null) {\r\n const token = this.peek();\r\n if (!token || token.type !== type) return false;\r\n if (value !== null && token.value !== value) return false;\r\n this.position += 1;\r\n return true;\r\n }\r\n\r\n expect(type, value = null, message = \"Invalid expression\") {\r\n const token = this.peek();\r\n if (!token || token.type !== type || (value !== null && token.value !== value)) {\r\n throw new CalcError(message);\r\n }\r\n return this.consume();\r\n }\r\n\r\n parse() {\r\n if (this.tokens.length === 0) throw new CalcError(\"Enter an expression\");\r\n const value = this.parseExpression();\r\n if (this.peek()) throw new CalcError(\"Invalid expression\");\r\n return value;\r\n }\r\n\r\n parseExpression() {\r\n return this.parseAdditive();\r\n }\r\n\r\n parseAdditive() {\r\n let left = this.parseMultiplicative();\r\n\r\n while (true) {\r\n if (this.match(\"operator\", \"+\")) {\r\n left += this.parseMultiplicative();\r\n } else if (this.match(\"operator\", \"-\")) {\r\n left -= this.parseMultiplicative();\r\n } else {\r\n break;\r\n }\r\n }\r\n\r\n return left;\r\n }\r\n\r\n parseMultiplicative() {\r\n let left = this.parseUnary();\r\n\r\n while (true) {\r\n if (this.match(\"operator\", \"*\")) {\r\n left *= this.parseUnary();\r\n } else if (this.match(\"operator\", \"\/\")) {\r\n const divisor = this.parseUnary();\r\n if (divisor === 0) throw new CalcError(\"Cannot divide by zero\");\r\n left \/= divisor;\r\n } else {\r\n break;\r\n }\r\n }\r\n\r\n return left;\r\n }\r\n\r\n parseUnary() {\r\n if (this.match(\"operator\", \"+\")) return +this.parseUnary();\r\n if (this.match(\"operator\", \"-\")) return -this.parseUnary();\r\n return this.parsePower();\r\n }\r\n\r\n parsePower() {\r\n let base = this.parsePostfix();\r\n if (this.match(\"operator\", \"^\")) {\r\n const exponent = this.parseUnary();\r\n const result = Math.pow(base, exponent);\r\n if (Number.isNaN(result)) throw new CalcError(\"Power operation is outside the real-number domain\");\r\n base = result;\r\n }\r\n return base;\r\n }\r\n\r\n parsePostfix() {\r\n let value = this.parsePrimary();\r\n\r\n while (true) {\r\n if (this.match(\"operator\", \"!\")) {\r\n value = factorial(value);\r\n } else if (this.match(\"operator\", \"%\")) {\r\n value \/= 100;\r\n } else {\r\n break;\r\n }\r\n }\r\n\r\n return value;\r\n }\r\n\r\n parsePrimary() {\r\n const token = this.peek();\r\n if (!token) throw new CalcError(\"Expression is incomplete\");\r\n\r\n if (token.type === \"number\") {\r\n this.consume();\r\n return token.value;\r\n }\r\n\r\n if (token.type === \"identifier\") {\r\n this.consume();\r\n const name = token.value;\r\n\r\n if (CONSTANT_NAMES.has(name)) {\r\n return this.resolveConstant(name);\r\n }\r\n\r\n if (!FUNCTION_NAMES.has(name)) {\r\n throw new CalcError(`Unknown function or constant: ${name}`);\r\n }\r\n\r\n this.expect(\"lparen\", \"(\", `Expected '(' after ${name}`);\r\n const args = [];\r\n\r\n if (!this.match(\"rparen\", \")\")) {\r\n do {\r\n args.push(this.parseExpression());\r\n } while (this.match(\"comma\", \",\"));\r\n this.expect(\"rparen\", \")\", \"Check parentheses\");\r\n }\r\n\r\n return this.callFunction(name, args);\r\n }\r\n\r\n if (this.match(\"lparen\", \"(\")) {\r\n const value = this.parseExpression();\r\n this.expect(\"rparen\", \")\", \"Check parentheses\");\r\n return value;\r\n }\r\n\r\n throw new CalcError(\"Invalid expression\");\r\n }\r\n\r\n resolveConstant(name) {\r\n if (name === \"pi\") return Math.PI;\r\n if (name === \"e\") return Math.E;\r\n if (name === \"phi\") return GOLDEN_RATIO;\r\n if (name === \"ans\") return state.previousAnswer;\r\n throw new CalcError(`Unknown constant: ${name}`);\r\n }\r\n\r\n callFunction(name, args) {\r\n const requireCount = (count) => {\r\n if (args.length !== count) throw new CalcError(`${name} requires ${count} argument${count === 1 ? \"\" : \"s\"}`);\r\n };\r\n\r\n const requireAtLeast = (count) => {\r\n if (args.length < count) throw new CalcError(`${name} requires at least ${count} arguments`);\r\n };\r\n\r\n switch (name) {\r\n case \"sin\": requireCount(1); return Math.sin(toRadians(args[0]));\r\n case \"cos\": requireCount(1); return Math.cos(toRadians(args[0]));\r\n case \"tan\": {\r\n requireCount(1);\r\n const radians = toRadians(args[0]);\r\n if (Math.abs(Math.cos(radians)) < 1e-14) throw new CalcError(\"tan is undefined at this angle\");\r\n return Math.tan(radians);\r\n }\r\n case \"asin\":\r\n requireCount(1);\r\n if (args[0] < -1 || args[0] > 1) throw new CalcError(\"asin input must be between -1 and 1\");\r\n return fromRadians(Math.asin(args[0]));\r\n case \"acos\":\r\n requireCount(1);\r\n if (args[0] < -1 || args[0] > 1) throw new CalcError(\"acos input must be between -1 and 1\");\r\n return fromRadians(Math.acos(args[0]));\r\n case \"atan\": requireCount(1); return fromRadians(Math.atan(args[0]));\r\n case \"sinh\": requireCount(1); return Math.sinh(args[0]);\r\n case \"cosh\": requireCount(1); return Math.cosh(args[0]);\r\n case \"tanh\": requireCount(1); return Math.tanh(args[0]);\r\n case \"asinh\": requireCount(1); return Math.asinh(args[0]);\r\n case \"acosh\":\r\n requireCount(1);\r\n if (args[0] < 1) throw new CalcError(\"acosh input must be at least 1\");\r\n return Math.acosh(args[0]);\r\n case \"atanh\":\r\n requireCount(1);\r\n if (args[0] <= -1 || args[0] >= 1) throw new CalcError(\"atanh input must be between -1 and 1\");\r\n return Math.atanh(args[0]);\r\n case \"log\":\r\n requireCount(1);\r\n if (args[0] <= 0) throw new CalcError(\"Logarithm input must be greater than zero\");\r\n return Math.log10(args[0]);\r\n case \"ln\":\r\n requireCount(1);\r\n if (args[0] <= 0) throw new CalcError(\"Logarithm input must be greater than zero\");\r\n return Math.log(args[0]);\r\n case \"log2\":\r\n requireCount(1);\r\n if (args[0] <= 0) throw new CalcError(\"Logarithm input must be greater than zero\");\r\n return Math.log2(args[0]);\r\n case \"logb\":\r\n requireCount(2);\r\n if (args[0] <= 0) throw new CalcError(\"Logarithm input must be greater than zero\");\r\n if (args[1] <= 0 || args[1] === 1) throw new CalcError(\"Logarithm base must be positive and not equal to 1\");\r\n return Math.log(args[0]) \/ Math.log(args[1]);\r\n case \"sqrt\":\r\n requireCount(1);\r\n if (args[0] < 0) throw new CalcError(\"Square root of a negative number is not real\");\r\n return Math.sqrt(args[0]);\r\n case \"cbrt\": requireCount(1); return Math.cbrt(args[0]);\r\n case \"root\": {\r\n requireCount(2);\r\n const [x, n] = args;\r\n if (n === 0) throw new CalcError(\"Root degree cannot be zero\");\r\n if (x < 0 && !nearlyInteger(n)) throw new CalcError(\"This root is outside the real-number domain\");\r\n if (x < 0 && Math.abs(Math.round(n)) % 2 === 0) throw new CalcError(\"Even root of a negative number is not real\");\r\n if (x < 0) return -Math.pow(-x, 1 \/ n);\r\n return Math.pow(x, 1 \/ n);\r\n }\r\n case \"abs\": requireCount(1); return Math.abs(args[0]);\r\n case \"floor\": requireCount(1); return Math.floor(args[0]);\r\n case \"ceil\": requireCount(1); return Math.ceil(args[0]);\r\n case \"round\": requireCount(1); return Math.round(args[0]);\r\n case \"trunc\": requireCount(1); return Math.trunc(args[0]);\r\n case \"sign\": requireCount(1); return Math.sign(args[0]);\r\n case \"min\": requireAtLeast(1); return Math.min(...args);\r\n case \"max\": requireAtLeast(1); return Math.max(...args);\r\n case \"gcd\": requireCount(2); return integerGcd(args[0], args[1]);\r\n case \"lcm\": requireCount(2); return integerLcm(args[0], args[1]);\r\n case \"ncr\": requireCount(2); return combination(args[0], args[1]);\r\n case \"npr\": requireCount(2); return permutation(args[0], args[1]);\r\n case \"mod\": {\r\n requireCount(2);\r\n if (args[1] === 0) throw new CalcError(\"Modulo divisor cannot be zero\");\r\n return args[0] % args[1];\r\n }\r\n case \"randbetween\": {\r\n requireCount(2);\r\n let [a, b] = args;\r\n if (!nearlyInteger(a) || !nearlyInteger(b)) throw new CalcError(\"randbetween requires integer bounds\");\r\n if (a > b) [a, b] = [b, a];\r\n return Math.floor(Math.random() * (b - a + 1)) + a;\r\n }\r\n default:\r\n throw new CalcError(`Unsupported function: ${name}`);\r\n }\r\n }\r\n }\r\n\r\n function tryEvaluateRelativePercentage(tokens) {\r\n if (tokens.length < 4) return null;\r\n const last = tokens[tokens.length - 1];\r\n if (last.type !== \"operator\" || last.value !== \"%\") return null;\r\n\r\n let depth = 0;\r\n const candidates = [];\r\n\r\n for (let i = 0; i < tokens.length - 1; i += 1) {\r\n const token = tokens[i];\r\n if (token.type === \"lparen\") depth += 1;\r\n if (token.type === \"rparen\") depth -= 1;\r\n\r\n if (depth === 0 && token.type === \"operator\" && (token.value === \"+\" || token.value === \"-\") && i > 0) {\r\n const previous = tokens[i - 1];\r\n const isUnary = previous.type === \"operator\" || previous.type === \"lparen\" || previous.type === \"comma\";\r\n if (!isUnary) candidates.push(i);\r\n }\r\n }\r\n\r\n if (candidates.length !== 1) return null;\r\n\r\n const operatorIndex = candidates[0];\r\n const leftTokens = tokens.slice(0, operatorIndex);\r\n const rightTokens = tokens.slice(operatorIndex + 1);\r\n if (!leftTokens.length || !rightTokens.length) return null;\r\n\r\n const base = new Parser(leftTokens).parse();\r\n const fraction = new Parser(rightTokens).parse();\r\n return tokens[operatorIndex].value === \"+\"\r\n ? base + (base * fraction)\r\n : base - (base * fraction);\r\n }\r\n\r\n function evaluateExpression(expression) {\r\n const tokens = tokenize(expression);\r\n const relativePercentageResult = tryEvaluateRelativePercentage(tokens);\r\n const parser = new Parser(tokens);\r\n let result = relativePercentageResult ?? parser.parse();\r\n\r\n if (Number.isNaN(result)) throw new CalcError(\"Result is not a real number\");\r\n if (!Number.isFinite(result)) throw new CalcError(\"Result is outside the supported numeric range\");\r\n\r\n result = roundFloatingNoise(normalizeNegativeZero(result));\r\n return result;\r\n }\r\n\r\n \/* =========================================================\r\n 08. RESULT FORMATTING\r\n ========================================================== *\/\r\n function formatExponent(exponent) {\r\n return exponent >= 0 ? `+${exponent}` : `${exponent}`;\r\n }\r\n\r\n function formatNormal(value) {\r\n const precision = state.precision === \"auto\" ? null : Number(state.precision);\r\n let normalized = normalizeNegativeZero(value);\r\n\r\n if (precision !== null) {\r\n normalized = Number(normalized.toFixed(precision));\r\n } else {\r\n normalized = roundFloatingNoise(normalized);\r\n }\r\n\r\n const absolute = Math.abs(normalized);\r\n if (absolute !== 0 && (absolute >= 1e15 || absolute < 1e-9)) {\r\n return normalized.toExponential(12).replace(\/\\.0+e\/, \"e\").replace(\/(\\.\\d*?[1-9])0+e\/, \"$1e\");\r\n }\r\n\r\n const raw = String(normalized);\r\n if (\/e\/i.test(raw)) return raw;\r\n\r\n const [integerPart, decimalPart] = raw.split(\".\");\r\n const sign = integerPart.startsWith(\"-\") ? \"-\" : \"\";\r\n const integerDigits = sign ? integerPart.slice(1) : integerPart;\r\n const grouped = integerDigits.replace(\/\\B(?=(\\d{3})+(?!\\d))\/g, \",\");\r\n return `${sign}${grouped}${decimalPart ? `.${decimalPart}` : \"\"}`;\r\n }\r\n\r\n function formatScientific(value) {\r\n if (value === 0) return \"0\";\r\n const digits = state.precision === \"auto\" ? 10 : clamp(Number(state.precision), 1, 12);\r\n const [coefficient, exponent] = value.toExponential(digits).split(\"e\");\r\n return `${Number(coefficient)} \u00d7 10^${Number(exponent)}`;\r\n }\r\n\r\n function formatEngineering(value) {\r\n if (value === 0) return \"0\";\r\n const exponent = Math.floor(Math.log10(Math.abs(value)) \/ 3) * 3;\r\n const coefficient = value \/ Math.pow(10, exponent);\r\n const digits = state.precision === \"auto\" ? 10 : clamp(Number(state.precision), 1, 12);\r\n const rounded = Number(coefficient.toPrecision(digits));\r\n return `${rounded} \u00d7 10^${exponent}`;\r\n }\r\n\r\n function formatResult(value) {\r\n if (!isFiniteNumber(value)) return \"Error\";\r\n if (state.numberFormat === \"scientific\") return formatScientific(value);\r\n if (state.numberFormat === \"engineering\") return formatEngineering(value);\r\n return formatNormal(value);\r\n }\r\n\r\n \/* =========================================================\r\n 09. INPUT EDITING\r\n ========================================================== *\/\r\n function getInputSelection() {\r\n const start = dom.expressionInput.selectionStart ?? dom.expressionInput.value.length;\r\n const end = dom.expressionInput.selectionEnd ?? start;\r\n return { start, end };\r\n }\r\n\r\n function setInputCursor(position) {\r\n requestAnimationFrame(() => {\r\n dom.expressionInput.focus();\r\n dom.expressionInput.setSelectionRange(position, position);\r\n });\r\n }\r\n\r\n function replaceSelection(text, cursorOffset = text.length) {\r\n const input = dom.expressionInput;\r\n const { start, end } = getInputSelection();\r\n const before = input.value.slice(0, start);\r\n const after = input.value.slice(end);\r\n\r\n input.value = before + text + after;\r\n state.expression = input.value;\r\n state.justEvaluated = false;\r\n const nextPosition = start + cursorOffset;\r\n setInputCursor(nextPosition);\r\n updateLivePreview();\r\n }\r\n\r\n function insertText(text) {\r\n if (state.justEvaluated && \/^[0-9.(A-Za-z]\/.test(text) && ![\"pi\", \"e\", \"phi\", \"ans\"].includes(text)) {\r\n clearCurrentExpression(false);\r\n } else if (state.justEvaluated && \/^[+\\-*\/^%]\/.test(text)) {\r\n dom.expressionInput.value = String(state.result);\r\n state.expression = dom.expressionInput.value;\r\n dom.expressionInput.setSelectionRange(dom.expressionInput.value.length, dom.expressionInput.value.length);\r\n }\r\n\r\n replaceSelection(text);\r\n }\r\n\r\n function smartParenthesis() {\r\n const value = dom.expressionInput.value;\r\n const { start } = getInputSelection();\r\n const before = value.slice(0, start);\r\n const opens = (before.match(\/\$\/g) || []).length;\r\n const closes = (before.match(\/\$\/g) || []).length;\r\n const previous = before.trim().slice(-1);\r\n\r\n const shouldClose = opens > closes && \/[\\dA-Za-z)!%]\/.test(previous);\r\n insertText(shouldClose ? \")\" : \"(\");\r\n }\r\n\r\n function backspaceInput() {\r\n const input = dom.expressionInput;\r\n const { start, end } = getInputSelection();\r\n\r\n if (start !== end) {\r\n input.setRangeText(\"\", start, end, \"end\");\r\n } else if (start > 0) {\r\n const before = input.value.slice(0, start);\r\n const knownSuffixes = [\"sqrt(\", \"asinh(\", \"acosh(\", \"atanh(\", \"sinh(\", \"cosh(\", \"tanh(\", \"asin(\", \"acos(\", \"atan(\", \"log2(\", \"floor(\", \"ceil(\", \"round(\", \"trunc(\", \"sign(\", \"sin(\", \"cos(\", \"tan(\", \"log(\", \"ln(\", \"abs(\", \"gcd(\", \"lcm(\", \"ncr(\", \"npr(\", \"mod(\", \"min(\", \"max(\", \"root(\"];\r\n const suffix = knownSuffixes.find(item => before.endsWith(item));\r\n const deleteCount = suffix ? suffix.length : 1;\r\n input.setRangeText(\"\", start - deleteCount, start, \"end\");\r\n }\r\n\r\n state.expression = input.value;\r\n state.justEvaluated = false;\r\n updateLivePreview();\r\n input.focus();\r\n }\r\n\r\n function clearCurrentExpression(resetResult = true) {\r\n dom.expressionInput.value = \"\";\r\n state.expression = \"\";\r\n state.justEvaluated = false;\r\n dom.previewOutput.textContent = \"\";\r\n if (resetResult) {\r\n state.result = 0;\r\n dom.resultOutput.textContent = \"0\";\r\n }\r\n clearMessage();\r\n dom.expressionInput.focus();\r\n }\r\n\r\n function toggleSign() {\r\n const input = dom.expressionInput;\r\n const { start, end } = getInputSelection();\r\n\r\n if (start !== end) {\r\n const selected = input.value.slice(start, end);\r\n input.setRangeText(`-(${selected})`, start, end, \"end\");\r\n } else if (input.value.trim()) {\r\n input.value = `-(${input.value})`;\r\n input.setSelectionRange(input.value.length, input.value.length);\r\n } else if (state.result !== 0) {\r\n input.value = String(-state.result);\r\n input.setSelectionRange(input.value.length, input.value.length);\r\n } else {\r\n input.value = \"-\";\r\n input.setSelectionRange(1, 1);\r\n }\r\n\r\n state.expression = input.value;\r\n state.justEvaluated = false;\r\n updateLivePreview();\r\n input.focus();\r\n }\r\n\r\n function wrapCurrentExpression(prefix, suffix = \")\") {\r\n const input = dom.expressionInput;\r\n const { start, end } = getInputSelection();\r\n\r\n if (start !== end) {\r\n const selected = input.value.slice(start, end);\r\n input.setRangeText(`${prefix}${selected}${suffix}`, start, end, \"end\");\r\n } else if (input.value.trim()) {\r\n input.value = `${prefix}${input.value}${suffix}`;\r\n input.setSelectionRange(input.value.length, input.value.length);\r\n } else if (state.justEvaluated || state.result !== 0) {\r\n input.value = `${prefix}${state.result}${suffix}`;\r\n input.setSelectionRange(input.value.length, input.value.length);\r\n } else {\r\n input.value = prefix + suffix;\r\n const cursor = prefix.length;\r\n input.setSelectionRange(cursor, cursor);\r\n }\r\n\r\n state.expression = input.value;\r\n state.justEvaluated = false;\r\n updateLivePreview();\r\n input.focus();\r\n }\r\n\r\n \/* =========================================================\r\n 10. EVALUATION & LIVE PREVIEW\r\n ========================================================== *\/\r\n function updateLivePreview() {\r\n state.expression = dom.expressionInput.value;\r\n clearMessage();\r\n\r\n if (!state.expression.trim()) {\r\n dom.previewOutput.textContent = \"\";\r\n return;\r\n }\r\n\r\n try {\r\n const result = evaluateExpression(state.expression);\r\n dom.previewOutput.textContent = `= ${formatResult(result)}`;\r\n } catch {\r\n dom.previewOutput.textContent = \"\";\r\n }\r\n }\r\n\r\n function evaluateCurrentExpression() {\r\n const expression = dom.expressionInput.value.trim();\r\n if (!expression) {\r\n showMessage(\"Enter an expression\", \"error\");\r\n return;\r\n }\r\n\r\n try {\r\n const result = evaluateExpression(expression);\r\n state.result = result;\r\n state.previousAnswer = result;\r\n state.justEvaluated = true;\r\n state.lastEvaluation = { expression, result };\r\n\r\n dom.resultOutput.textContent = formatResult(result);\r\n dom.previewOutput.textContent = \"\";\r\n clearMessage();\r\n\r\n addHistory(expression, result);\r\n } catch (error) {\r\n const message = error instanceof CalcError ? error.message : \"Invalid expression\";\r\n showMessage(message, \"error\");\r\n dom.previewOutput.textContent = \"\";\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 11. SHIFT \/ SECOND FUNCTIONS\r\n ========================================================== *\/\r\n function setSecondMode(enabled) {\r\n state.secondMode = Boolean(enabled);\r\n dom.shiftIndicator.classList.toggle(\"is-active\", state.secondMode);\r\n dom.shiftButton.classList.toggle(\"key-shifted\", state.secondMode);\r\n dom.shiftButton.setAttribute(\"aria-pressed\", String(state.secondMode));\r\n\r\n document.querySelectorAll(\".shiftable\").forEach(button => {\r\n if (state.secondMode) {\r\n button.textContent = button.dataset.shiftLabel || button.textContent;\r\n\r\n if (button.dataset.shiftInsert) button.dataset.insert = button.dataset.shiftInsert;\r\n else delete button.dataset.insert;\r\n\r\n if (button.dataset.shiftAction) button.dataset.action = button.dataset.shiftAction;\r\n else delete button.dataset.action;\r\n } else {\r\n button.textContent = button.dataset.normalLabel || button.textContent;\r\n\r\n if (button.dataset.normalInsert) button.dataset.insert = button.dataset.normalInsert;\r\n else delete button.dataset.insert;\r\n\r\n if (button.dataset.normalAction) button.dataset.action = button.dataset.normalAction;\r\n else delete button.dataset.action;\r\n }\r\n });\r\n }\r\n\r\n \/* =========================================================\r\n 12. MEMORY\r\n ========================================================== *\/\r\n function resolveCurrentNumericValue() {\r\n const expression = dom.expressionInput.value.trim();\r\n if (expression) return evaluateExpression(expression);\r\n return state.result;\r\n }\r\n\r\n function updateMemoryIndicator() {\r\n dom.memoryIndicator.classList.toggle(\"is-active\", state.memory !== 0);\r\n dom.memoryIndicator.title = state.memory !== 0 ? `Memory: ${formatResult(state.memory)}` : \"Memory is empty\";\r\n }\r\n\r\n function memoryAction(action) {\r\n try {\r\n switch (action) {\r\n case \"memory-clear\":\r\n state.memory = 0;\r\n showMessage(\"Memory cleared\", \"success\");\r\n break;\r\n case \"memory-recall\":\r\n insertText(String(state.memory));\r\n showMessage(\"Memory recalled\", \"success\");\r\n break;\r\n case \"memory-store\":\r\n state.memory = resolveCurrentNumericValue();\r\n showMessage(\"Value stored in memory\", \"success\");\r\n break;\r\n case \"memory-add\":\r\n state.memory += resolveCurrentNumericValue();\r\n showMessage(\"Added to memory\", \"success\");\r\n break;\r\n case \"memory-subtract\":\r\n state.memory -= resolveCurrentNumericValue();\r\n showMessage(\"Subtracted from memory\", \"success\");\r\n break;\r\n default:\r\n return;\r\n }\r\n state.memory = roundFloatingNoise(state.memory);\r\n updateMemoryIndicator();\r\n } catch (error) {\r\n showMessage(error instanceof CalcError ? error.message : \"Unable to use memory\", \"error\");\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 13. HISTORY\r\n ========================================================== *\/\r\n function loadHistory() {\r\n if (!state.historyPersistence) {\r\n state.history = [];\r\n return;\r\n }\r\n\r\n const raw = safeStorageGet(STORAGE_KEYS.history);\r\n if (!raw) return;\r\n\r\n try {\r\n const parsed = JSON.parse(raw);\r\n if (Array.isArray(parsed)) {\r\n state.history = parsed\r\n .filter(item => item && typeof item.expression === \"string\" && isFiniteNumber(item.result))\r\n .slice(0, MAX_HISTORY);\r\n }\r\n } catch {\r\n state.history = [];\r\n }\r\n }\r\n\r\n function persistHistory() {\r\n if (!state.historyPersistence) {\r\n safeStorageRemove(STORAGE_KEYS.history);\r\n return;\r\n }\r\n safeStorageSet(STORAGE_KEYS.history, JSON.stringify(state.history.slice(0, MAX_HISTORY)));\r\n }\r\n\r\n function addHistory(expression, result) {\r\n const entry = {\r\n id: `${Date.now()}-${Math.random().toString(36).slice(2, 8)}`,\r\n expression,\r\n result,\r\n timestamp: Date.now()\r\n };\r\n\r\n state.history.unshift(entry);\r\n state.history = state.history.slice(0, MAX_HISTORY);\r\n persistHistory();\r\n renderHistory();\r\n }\r\n\r\n function renderHistory() {\r\n dom.historyList.innerHTML = \"\";\r\n\r\n if (!state.history.length) {\r\n const empty = document.createElement(\"div\");\r\n empty.className = \"history-empty\";\r\n empty.textContent = \"Your completed calculations will appear here.\";\r\n dom.historyList.appendChild(empty);\r\n return;\r\n }\r\n\r\n const fragment = document.createDocumentFragment();\r\n\r\n state.history.forEach(entry => {\r\n const item = document.createElement(\"article\");\r\n item.className = \"history-item\";\r\n item.dataset.historyId = entry.id;\r\n\r\n const expressionButton = document.createElement(\"button\");\r\n expressionButton.className = \"history-expression\";\r\n expressionButton.type = \"button\";\r\n expressionButton.textContent = entry.expression;\r\n expressionButton.title = \"Load expression\";\r\n expressionButton.dataset.historyAction = \"expression\";\r\n\r\n const resultButton = document.createElement(\"button\");\r\n resultButton.className = \"history-result\";\r\n resultButton.type = \"button\";\r\n resultButton.textContent = `= ${formatResult(entry.result)}`;\r\n resultButton.title = \"Use result\";\r\n resultButton.dataset.historyAction = \"result\";\r\n\r\n const time = document.createElement(\"time\");\r\n time.className = \"history-time\";\r\n time.dateTime = new Date(entry.timestamp).toISOString();\r\n time.textContent = new Date(entry.timestamp).toLocaleTimeString([], { hour: \"2-digit\", minute: \"2-digit\" });\r\n\r\n const removeButton = document.createElement(\"button\");\r\n removeButton.className = \"history-delete\";\r\n removeButton.type = \"button\";\r\n removeButton.ariaLabel = \"Delete history entry\";\r\n removeButton.title = \"Delete\";\r\n removeButton.textContent = \"\u00d7\";\r\n removeButton.dataset.historyAction = \"delete\";\r\n\r\n item.append(expressionButton, resultButton, time, removeButton);\r\n fragment.appendChild(item);\r\n });\r\n\r\n dom.historyList.appendChild(fragment);\r\n }\r\n\r\n function handleHistoryClick(event) {\r\n const button = event.target.closest(\"button[data-history-action]\");\r\n if (!button) return;\r\n\r\n const item = button.closest(\".history-item\");\r\n const entry = state.history.find(historyEntry => historyEntry.id === item?.dataset.historyId);\r\n if (!entry) return;\r\n\r\n const action = button.dataset.historyAction;\r\n\r\n if (action === \"delete\") {\r\n state.history = state.history.filter(historyEntry => historyEntry.id !== entry.id);\r\n persistHistory();\r\n renderHistory();\r\n return;\r\n }\r\n\r\n if (action === \"expression\") {\r\n dom.expressionInput.value = entry.expression;\r\n state.expression = entry.expression;\r\n state.justEvaluated = false;\r\n dom.expressionInput.focus();\r\n dom.expressionInput.setSelectionRange(entry.expression.length, entry.expression.length);\r\n updateLivePreview();\r\n }\r\n\r\n if (action === \"result\") {\r\n insertText(String(entry.result));\r\n }\r\n\r\n closeMobileHistory();\r\n }\r\n\r\n function clearHistory() {\r\n state.history = [];\r\n persistHistory();\r\n renderHistory();\r\n showMessage(\"History cleared\", \"success\");\r\n }\r\n\r\n \/* =========================================================\r\n 14. COPY & FRACTION\r\n ========================================================== *\/\r\n async function copyResult() {\r\n const text = String(state.result);\r\n if (!text || !isFiniteNumber(state.result)) {\r\n showMessage(\"Nothing to copy\", \"error\");\r\n return;\r\n }\r\n\r\n try {\r\n if (navigator.clipboard && window.isSecureContext) {\r\n await navigator.clipboard.writeText(text);\r\n } else {\r\n const helper = document.createElement(\"textarea\");\r\n helper.value = text;\r\n helper.setAttribute(\"readonly\", \"\");\r\n helper.style.position = \"absolute\";\r\n helper.style.left = \"-9999px\";\r\n document.body.appendChild(helper);\r\n helper.select();\r\n const copied = document.execCommand(\"copy\");\r\n helper.remove();\r\n if (!copied) throw new Error(\"Copy failed\");\r\n }\r\n showMessage(\"Copied\", \"success\");\r\n } catch {\r\n showMessage(\"Copy is not available in this browser\", \"error\");\r\n }\r\n }\r\n\r\n function decimalToFraction(value, maxDenominator = 100000) {\r\n if (!isFiniteNumber(value)) return null;\r\n if (nearlyInteger(value)) return `${Math.round(value)}\/1`;\r\n\r\n const sign = value < 0 ? -1 : 1;\r\n let x = Math.abs(value);\r\n let h1 = 1, h0 = 0, k1 = 0, k0 = 1;\r\n let bestH = 0, bestK = 1;\r\n\r\n for (let i = 0; i < 40; i += 1) {\r\n const a = Math.floor(x);\r\n const h2 = a * h1 + h0;\r\n const k2 = a * k1 + k0;\r\n if (k2 > maxDenominator) break;\r\n bestH = h2;\r\n bestK = k2;\r\n if (Math.abs(value - sign * bestH \/ bestK) < 1e-12) break;\r\n h0 = h1; h1 = h2;\r\n k0 = k1; k1 = k2;\r\n x = 1 \/ (x - a);\r\n if (!Number.isFinite(x)) break;\r\n }\r\n\r\n const gcd = integerGcd(bestH, bestK);\r\n return `${sign * (bestH \/ gcd)}\/${bestK \/ gcd}`;\r\n }\r\n\r\n function showFraction() {\r\n if (!isFiniteNumber(state.result)) {\r\n showMessage(\"No numeric result available\", \"error\");\r\n return;\r\n }\r\n const fraction = decimalToFraction(state.result);\r\n showMessage(`Fraction: ${fraction}`, \"success\");\r\n }\r\n\r\n \/* =========================================================\r\n 15. THEMES & SETTINGS\r\n ========================================================== *\/\r\n function applyTheme(theme, persist = true) {\r\n state.theme = theme === \"light\" ? \"light\" : \"dark\";\r\n dom.html.dataset.theme = state.theme;\r\n dom.themeSelect.value = state.theme;\r\n dom.themeButton.title = state.theme === \"dark\" ? \"Switch to light theme\" : \"Switch to dark theme\";\r\n if (persist) safeStorageSet(STORAGE_KEYS.theme, state.theme);\r\n }\r\n\r\n function applyAngleMode(mode, persist = true) {\r\n if (![\"DEG\", \"RAD\", \"GRAD\"].includes(mode)) return;\r\n state.angleMode = mode;\r\n dom.angleIndicator.textContent = mode;\r\n document.querySelectorAll(\"[data-angle]\").forEach(button => {\r\n button.setAttribute(\"aria-pressed\", String(button.dataset.angle === mode));\r\n });\r\n if (persist) safeStorageSet(STORAGE_KEYS.angle, mode);\r\n updateLivePreview();\r\n }\r\n\r\n function applyNumberFormat(format, persist = true) {\r\n if (![\"normal\", \"scientific\", \"engineering\"].includes(format)) return;\r\n state.numberFormat = format;\r\n dom.formatSelect.value = format;\r\n dom.formatIndicator.textContent = format.toUpperCase();\r\n if (persist) safeStorageSet(STORAGE_KEYS.format, format);\r\n dom.resultOutput.textContent = formatResult(state.result);\r\n renderHistory();\r\n updateLivePreview();\r\n }\r\n\r\n function applyPrecision(precision, persist = true) {\r\n const allowed = new Set([\"auto\", \"4\", \"6\", \"8\", \"10\", \"12\"]);\r\n state.precision = allowed.has(String(precision)) ? String(precision) : \"auto\";\r\n dom.precisionSelect.value = state.precision;\r\n if (persist) safeStorageSet(STORAGE_KEYS.precision, state.precision);\r\n dom.resultOutput.textContent = formatResult(state.result);\r\n renderHistory();\r\n updateLivePreview();\r\n }\r\n\r\n function applyHistoryPersistence(value, persist = true) {\r\n state.historyPersistence = value === true || value === \"on\";\r\n dom.historyPersistenceSelect.value = state.historyPersistence ? \"on\" : \"off\";\r\n if (persist) safeStorageSet(STORAGE_KEYS.historyPersistence, state.historyPersistence ? \"on\" : \"off\");\r\n if (!state.historyPersistence) safeStorageRemove(STORAGE_KEYS.history);\r\n else persistHistory();\r\n }\r\n\r\n function openSettings() {\r\n dom.settingsBackdrop.hidden = false;\r\n dom.closeSettingsButton.focus();\r\n }\r\n\r\n function closeSettings() {\r\n dom.settingsBackdrop.hidden = true;\r\n dom.settingsButton.focus();\r\n }\r\n\r\n function resetSettings() {\r\n applyTheme(window.matchMedia?.(\"(prefers-color-scheme: light)\").matches ? \"light\" : \"dark\");\r\n applyAngleMode(\"DEG\");\r\n applyNumberFormat(\"normal\");\r\n applyPrecision(\"auto\");\r\n applyHistoryPersistence(true);\r\n showMessage(\"Settings reset\", \"success\");\r\n }\r\n\r\n function loadSettings() {\r\n const preferredTheme = window.matchMedia?.(\"(prefers-color-scheme: light)\").matches ? \"light\" : \"dark\";\r\n applyTheme(safeStorageGet(STORAGE_KEYS.theme) || preferredTheme, false);\r\n applyAngleMode(safeStorageGet(STORAGE_KEYS.angle) || \"DEG\", false);\r\n applyNumberFormat(safeStorageGet(STORAGE_KEYS.format) || \"normal\", false);\r\n applyPrecision(safeStorageGet(STORAGE_KEYS.precision) || \"auto\", false);\r\n applyHistoryPersistence(safeStorageGet(STORAGE_KEYS.historyPersistence) !== \"off\", false);\r\n }\r\n\r\n \/* =========================================================\r\n 16. APPLICATION MODES\r\n ========================================================== *\/\r\n function setApplicationMode(mode) {\r\n state.currentMode = mode === \"converter\" ? \"converter\" : \"scientific\";\r\n const scientific = state.currentMode === \"scientific\";\r\n dom.scientificWorkspace.hidden = !scientific;\r\n dom.converterWorkspace.hidden = scientific;\r\n dom.scientificModeButton.setAttribute(\"aria-pressed\", String(scientific));\r\n dom.converterModeButton.setAttribute(\"aria-pressed\", String(!scientific));\r\n if (scientific) dom.expressionInput.focus();\r\n }\r\n\r\n \/* =========================================================\r\n 17. UNIT CONVERTER DATA & ENGINE\r\n ========================================================== *\/\r\n const UNIT_DATA = {\r\n Length: {\r\n base: \"m\",\r\n formula: \"Converted through metres\",\r\n units: {\r\n mm: { label: \"Millimetres (mm)\", factor: 0.001 },\r\n cm: { label: \"Centimetres (cm)\", factor: 0.01 },\r\n m: { label: \"Metres (m)\", factor: 1 },\r\n km: { label: \"Kilometres (km)\", factor: 1000 },\r\n in: { label: \"Inches (in)\", factor: 0.0254 },\r\n ft: { label: \"Feet (ft)\", factor: 0.3048 },\r\n yd: { label: \"Yards (yd)\", factor: 0.9144 },\r\n mi: { label: \"Miles (mi)\", factor: 1609.344 }\r\n }\r\n },\r\n Mass: {\r\n base: \"kg\",\r\n formula: \"Converted through kilograms\",\r\n units: {\r\n mg: { label: \"Milligrams (mg)\", factor: 1e-6 },\r\n g: { label: \"Grams (g)\", factor: 0.001 },\r\n kg: { label: \"Kilograms (kg)\", factor: 1 },\r\n oz: { label: \"Ounces (oz)\", factor: 0.028349523125 },\r\n lb: { label: \"Pounds (lb)\", factor: 0.45359237 }\r\n }\r\n },\r\n Temperature: {\r\n base: \"C\",\r\n formula: \"Uses exact temperature offset\/scale formulas\",\r\n units: {\r\n C: { label: \"Celsius (\u00b0C)\" },\r\n F: { label: \"Fahrenheit (\u00b0F)\" },\r\n K: { label: \"Kelvin (K)\" }\r\n }\r\n },\r\n Area: {\r\n base: \"m2\",\r\n formula: \"Converted through square metres\",\r\n units: {\r\n m2: { label: \"Square metres (m\u00b2)\", factor: 1 },\r\n km2: { label: \"Square kilometres (km\u00b2)\", factor: 1e6 },\r\n ft2: { label: \"Square feet (ft\u00b2)\", factor: 0.09290304 },\r\n acre: { label: \"Acres\", factor: 4046.8564224 },\r\n hectare: { label: \"Hectares\", factor: 10000 }\r\n }\r\n },\r\n Volume: {\r\n base: \"L\",\r\n formula: \"Converted through litres (US customary cup\/gallon)\",\r\n units: {\r\n mL: { label: \"Millilitres (mL)\", factor: 0.001 },\r\n L: { label: \"Litres (L)\", factor: 1 },\r\n cup: { label: \"US cups\", factor: 0.2365882365 },\r\n gallon: { label: \"US gallons\", factor: 3.785411784 }\r\n }\r\n },\r\n Speed: {\r\n base: \"mps\",\r\n formula: \"Converted through metres per second\",\r\n units: {\r\n mps: { label: \"Metres\/second (m\/s)\", factor: 1 },\r\n kmh: { label: \"Kilometres\/hour (km\/h)\", factor: 0.2777777777777778 },\r\n mph: { label: \"Miles\/hour (mph)\", factor: 0.44704 }\r\n }\r\n },\r\n Time: {\r\n base: \"s\",\r\n formula: \"Converted through seconds\",\r\n units: {\r\n s: { label: \"Seconds\", factor: 1 },\r\n min: { label: \"Minutes\", factor: 60 },\r\n h: { label: \"Hours\", factor: 3600 },\r\n d: { label: \"Days\", factor: 86400 }\r\n }\r\n }\r\n };\r\n\r\n function temperatureToCelsius(value, unit) {\r\n if (unit === \"C\") return value;\r\n if (unit === \"F\") return (value - 32) * 5 \/ 9;\r\n if (unit === \"K\") return value - 273.15;\r\n return value;\r\n }\r\n\r\n function celsiusToTemperature(value, unit) {\r\n if (unit === \"C\") return value;\r\n if (unit === \"F\") return value * 9 \/ 5 + 32;\r\n if (unit === \"K\") return value + 273.15;\r\n return value;\r\n }\r\n\r\n function convertUnits(category, value, fromUnit, toUnit) {\r\n const group = UNIT_DATA[category];\r\n if (!group) throw new Error(\"Unknown category\");\r\n\r\n if (category === \"Temperature\") {\r\n const celsius = temperatureToCelsius(value, fromUnit);\r\n const result = celsiusToTemperature(celsius, toUnit);\r\n if (toUnit === \"K\" && result < 0) throw new CalcError(\"Temperature cannot be below absolute zero\");\r\n return result;\r\n }\r\n\r\n const from = group.units[fromUnit];\r\n const to = group.units[toUnit];\r\n if (!from || !to) throw new Error(\"Unknown unit\");\r\n return value * from.factor \/ to.factor;\r\n }\r\n\r\n function populateConverterCategories() {\r\n dom.converterCategory.innerHTML = \"\";\r\n Object.keys(UNIT_DATA).forEach(category => {\r\n const option = document.createElement(\"option\");\r\n option.value = category;\r\n option.textContent = category;\r\n dom.converterCategory.appendChild(option);\r\n });\r\n dom.converterCategory.value = \"Length\";\r\n populateConverterUnits();\r\n }\r\n\r\n function populateConverterUnits() {\r\n const category = dom.converterCategory.value;\r\n const group = UNIT_DATA[category];\r\n dom.converterFrom.innerHTML = \"\";\r\n dom.converterTo.innerHTML = \"\";\r\n\r\n Object.entries(group.units).forEach(([key, data]) => {\r\n const fromOption = document.createElement(\"option\");\r\n fromOption.value = key;\r\n fromOption.textContent = data.label;\r\n dom.converterFrom.appendChild(fromOption);\r\n\r\n const toOption = fromOption.cloneNode(true);\r\n dom.converterTo.appendChild(toOption);\r\n });\r\n\r\n const keys = Object.keys(group.units);\r\n dom.converterFrom.value = keys[0];\r\n dom.converterTo.value = keys[Math.min(1, keys.length - 1)];\r\n dom.converterFormula.textContent = group.formula;\r\n updateConverter();\r\n }\r\n\r\n function updateConverter() {\r\n const value = Number(dom.converterValue.value);\r\n if (!Number.isFinite(value)) {\r\n dom.converterResult.textContent = \"Enter a valid number\";\r\n return;\r\n }\r\n\r\n try {\r\n const result = convertUnits(\r\n dom.converterCategory.value,\r\n value,\r\n dom.converterFrom.value,\r\n dom.converterTo.value\r\n );\r\n dom.converterResult.textContent = formatNormal(roundFloatingNoise(result));\r\n } catch (error) {\r\n dom.converterResult.textContent = error instanceof CalcError ? error.message : \"Conversion error\";\r\n }\r\n }\r\n\r\n function swapConverterUnits() {\r\n const from = dom.converterFrom.value;\r\n dom.converterFrom.value = dom.converterTo.value;\r\n dom.converterTo.value = from;\r\n updateConverter();\r\n }\r\n\r\n \/* =========================================================\r\n 18. MOBILE HISTORY\r\n ========================================================== *\/\r\n function openMobileHistory() {\r\n dom.historyPanel.classList.add(\"is-open\");\r\n dom.mobileHistoryBackdrop.hidden = false;\r\n }\r\n\r\n function closeMobileHistory() {\r\n dom.historyPanel.classList.remove(\"is-open\");\r\n dom.mobileHistoryBackdrop.hidden = true;\r\n }\r\n\r\n \/* =========================================================\r\n 19. CALCULATOR BUTTON ACTIONS\r\n ========================================================== *\/\r\n function handleCalculatorButton(button) {\r\n const action = button.dataset.action;\r\n const insert = button.dataset.insert;\r\n\r\n if (insert !== undefined) {\r\n insertText(insert);\r\n if (state.secondMode && button.classList.contains(\"shiftable\")) setSecondMode(false);\r\n return;\r\n }\r\n\r\n switch (action) {\r\n case \"evaluate\":\r\n evaluateCurrentExpression();\r\n break;\r\n case \"clear\":\r\n clearCurrentExpression(true);\r\n break;\r\n case \"backspace\":\r\n backspaceInput();\r\n break;\r\n case \"smart-parenthesis\":\r\n smartParenthesis();\r\n break;\r\n case \"toggle-sign\":\r\n toggleSign();\r\n break;\r\n case \"shift\":\r\n setSecondMode(!state.secondMode);\r\n break;\r\n case \"square\":\r\n wrapCurrentExpression(\"(\", \")^2\");\r\n break;\r\n case \"cube\":\r\n wrapCurrentExpression(\"(\", \")^3\");\r\n break;\r\n case \"reciprocal\":\r\n wrapCurrentExpression(\"1\/(\", \")\");\r\n break;\r\n case \"random\":\r\n insertText(String(Math.random()));\r\n break;\r\n case \"memory-clear\":\r\n case \"memory-recall\":\r\n case \"memory-add\":\r\n case \"memory-subtract\":\r\n case \"memory-store\":\r\n memoryAction(action);\r\n break;\r\n default:\r\n break;\r\n }\r\n\r\n if (state.secondMode && button.classList.contains(\"shiftable\")) setSecondMode(false);\r\n }\r\n\r\n \/* =========================================================\r\n 20. KEYBOARD INPUT\r\n ========================================================== *\/\r\n function flashMatchingKey(key) {\r\n const selectorMap = {\r\n \"+\": '[data-insert=\"+\"]',\r\n \"-\": '[data-insert=\"-\"]',\r\n \"*\": '[data-insert=\"\u00d7\"]',\r\n \"\/\": '[data-insert=\"\u00f7\"]',\r\n \"^\": '[data-insert=\"^\"]',\r\n \"%\": '[data-insert=\"%\"]',\r\n \"(\": '[data-insert=\"(\"]',\r\n \")\": '[data-insert=\")\"]',\r\n \".\": '[data-insert=\".\"]'\r\n };\r\n\r\n const selector = \/\\d\/.test(key) ? `[data-insert=\"${key}\"]` : selectorMap[key];\r\n if (!selector) return;\r\n const button = document.querySelector(selector);\r\n if (!button) return;\r\n button.classList.add(\"is-flashed\");\r\n window.setTimeout(() => button.classList.remove(\"is-flashed\"), 120);\r\n }\r\n\r\n function handleKeyboard(event) {\r\n if (state.currentMode !== \"scientific\") return;\r\n if (dom.settingsBackdrop.hidden === false) return;\r\n\r\n const inputFocused = document.activeElement === dom.expressionInput;\r\n if (!inputFocused) return;\r\n\r\n if (event.key === \"Enter\") {\r\n event.preventDefault();\r\n evaluateCurrentExpression();\r\n return;\r\n }\r\n\r\n if (event.key === \"Escape\") {\r\n event.preventDefault();\r\n clearCurrentExpression(true);\r\n return;\r\n }\r\n\r\n if (event.key === \"Backspace\") {\r\n event.preventDefault();\r\n backspaceInput();\r\n return;\r\n }\r\n\r\n const permitted = \/^[0-9+\\-*\/^().,%]$\/;\r\n if (permitted.test(event.key)) {\r\n event.preventDefault();\r\n const displayKey = event.key === \"*\" ? \"\u00d7\" : event.key === \"\/\" ? \"\u00f7\" : event.key;\r\n insertText(displayKey);\r\n flashMatchingKey(event.key);\r\n return;\r\n }\r\n\r\n if (\/^[A-Za-z]$\/.test(event.key)) {\r\n \/\/ Let browser type function names naturally into the focused input.\r\n return;\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 21. EVENT BINDINGS\r\n ========================================================== *\/\r\n function bindEvents() {\r\n document.querySelectorAll(\".calc-key, .tiny-button\").forEach(button => {\r\n if (button.dataset.angle) {\r\n button.addEventListener(\"click\", () => applyAngleMode(button.dataset.angle));\r\n } else {\r\n button.addEventListener(\"click\", () => handleCalculatorButton(button));\r\n }\r\n });\r\n\r\n dom.expressionInput.addEventListener(\"input\", () => {\r\n state.expression = dom.expressionInput.value;\r\n state.justEvaluated = false;\r\n updateLivePreview();\r\n });\r\n\r\n dom.expressionInput.addEventListener(\"keydown\", handleKeyboard);\r\n\r\n dom.copyButton.addEventListener(\"click\", copyResult);\r\n dom.fractionButton.addEventListener(\"click\", showFraction);\r\n dom.themeButton.addEventListener(\"click\", () => applyTheme(state.theme === \"dark\" ? \"light\" : \"dark\"));\r\n\r\n dom.scientificModeButton.addEventListener(\"click\", () => setApplicationMode(\"scientific\"));\r\n dom.converterModeButton.addEventListener(\"click\", () => setApplicationMode(\"converter\"));\r\n\r\n dom.historyList.addEventListener(\"click\", handleHistoryClick);\r\n dom.clearHistoryButton.addEventListener(\"click\", clearHistory);\r\n dom.mobileHistoryButton.addEventListener(\"click\", openMobileHistory);\r\n dom.mobileHistoryBackdrop.addEventListener(\"click\", closeMobileHistory);\r\n\r\n dom.settingsButton.addEventListener(\"click\", openSettings);\r\n dom.closeSettingsButton.addEventListener(\"click\", closeSettings);\r\n dom.doneSettingsButton.addEventListener(\"click\", closeSettings);\r\n dom.resetSettingsButton.addEventListener(\"click\", resetSettings);\r\n\r\n dom.settingsBackdrop.addEventListener(\"click\", event => {\r\n if (event.target === dom.settingsBackdrop) closeSettings();\r\n });\r\n\r\n dom.themeSelect.addEventListener(\"change\", () => applyTheme(dom.themeSelect.value));\r\n dom.formatSelect.addEventListener(\"change\", () => applyNumberFormat(dom.formatSelect.value));\r\n dom.precisionSelect.addEventListener(\"change\", () => applyPrecision(dom.precisionSelect.value));\r\n dom.historyPersistenceSelect.addEventListener(\"change\", () => applyHistoryPersistence(dom.historyPersistenceSelect.value));\r\n\r\n dom.converterCategory.addEventListener(\"change\", populateConverterUnits);\r\n dom.converterValue.addEventListener(\"input\", updateConverter);\r\n dom.converterFrom.addEventListener(\"change\", updateConverter);\r\n dom.converterTo.addEventListener(\"change\", updateConverter);\r\n dom.swapUnitsButton.addEventListener(\"click\", swapConverterUnits);\r\n\r\n window.addEventListener(\"resize\", () => {\r\n if (window.innerWidth > 820) closeMobileHistory();\r\n });\r\n }\r\n\r\n \/* =========================================================\r\n 22. SELF-TESTS\r\n ========================================================== *\/\r\n function runSelfTests() {\r\n const originalMode = state.angleMode;\r\n const tests = [\r\n [\"2+2\", 4],\r\n [\"2+3*4\", 14],\r\n [\"(2+3)*4\", 20],\r\n [\"10\/2+3\", 8],\r\n [\"2^3\", 8],\r\n [\"2^3^2\", 512],\r\n [\"sqrt(144)\", 12],\r\n [\"5!\", 120],\r\n [\"0!\", 1],\r\n [\"log(100)\", 2],\r\n [\"ln(e)\", 1],\r\n [\"0.1+0.2\", 0.3],\r\n [\"ncr(5,2)\", 10],\r\n [\"npr(5,2)\", 20],\r\n [\"logb(8,2)\", 3],\r\n [\"200*10%\", 20],\r\n [\"200+10%\", 220],\r\n [\"200-10%\", 180],\r\n [\"2(3+4)\", 14],\r\n [\"2pi\", 2 * Math.PI],\r\n [\"(2+3)(4+5)\", 45],\r\n [\"-5+10\", 5],\r\n [\"2^-3\", 0.125],\r\n [\"sqrt(0)\", 0]\r\n ];\r\n\r\n const failures = [];\r\n\r\n try {\r\n state.angleMode = \"DEG\";\r\n tests.push([\"sin(30)\", 0.5], [\"cos(60)\", 0.5], [\"tan(45)\", 1]);\r\n\r\n for (const [expression, expected] of tests) {\r\n const actual = evaluateExpression(expression);\r\n if (Math.abs(actual - expected) > 1e-10 * Math.max(1, Math.abs(expected))) {\r\n failures.push({ expression, expected, actual });\r\n }\r\n }\r\n\r\n state.angleMode = \"RAD\";\r\n const radActual = evaluateExpression(\"sin(pi\/2)\");\r\n if (Math.abs(radActual - 1) > 1e-10) failures.push({ expression: \"sin(pi\/2)\", expected: 1, actual: radActual });\r\n\r\n const errorTests = [\"1\/0\", \"sqrt(-1)\", \"log(0)\", \"log(-5)\", \"(-5)!\"];\r\n for (const expression of errorTests) {\r\n let threw = false;\r\n try {\r\n evaluateExpression(expression);\r\n } catch {\r\n threw = true;\r\n }\r\n if (!threw) failures.push({ expression, expected: \"error\", actual: \"no error\" });\r\n }\r\n } finally {\r\n state.angleMode = originalMode;\r\n }\r\n\r\n if (failures.length) {\r\n console.warn(\"NOVA calculator self-test failures:\", failures);\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 23. INITIALIZATION\r\n ========================================================== *\/\r\n function initialize() {\r\n loadSettings();\r\n loadHistory();\r\n renderHistory();\r\n populateConverterCategories();\r\n bindEvents();\r\n updateMemoryIndicator();\r\n setSecondMode(false);\r\n setApplicationMode(\"scientific\");\r\n dom.resultOutput.textContent = formatResult(0);\r\n runSelfTests();\r\n dom.expressionInput.focus();\r\n }\r\n\r\n initialize();\r\n <\/script>\r\n<\/body>\r\n<\/html>\r\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>NOVA Scientific Calculator Precision workspace NOVA Scientific Scientific Converter \u2315 \u25d0 \u2699 DEG M 2nd NORMAL a\/b Copy Expression 0 DEG RAD GRAD MC MR M+ M\u2212 MS 2nd ( ) ( ) \u03c0 e sin cos tan sinh cosh tanh x\u00b2 x\u00b3 x\u02b8 \u221ax \u221bx \u02b8\u221ax 10\u02e3 e\u02e3 2\u02e3 log ln log\u2082 |x| x! […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"elementor_canvas","meta":{"footnotes":""},"class_list":["post-67","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/pages\/67","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=67"}],"version-history":[{"count":4,"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/pages\/67\/revisions"}],"predecessor-version":[{"id":71,"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/pages\/67\/revisions\/71"}],"wp:attachment":[{"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=67"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

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\n\t\t\t\t\t\r\n\r\n\r\n \r\n \r\n \r\n NOVA Scientific Calculator<\/title>\r\n\r\n <style>\r\n \/* =========================================================\r\n 01. DESIGN TOKENS\r\n ========================================================== *\/\r\n :root {\r\n color-scheme: dark;\r\n --bg: #0e1117;\r\n --surface: #151a23;\r\n --surface-2: #1b2230;\r\n --surface-3: #222b3a;\r\n --display: #0b0e13;\r\n --text: #f5f7fb;\r\n --muted: #9ba6b5;\r\n --subtle: #6f7b8b;\r\n --border: #2a3443;\r\n --border-strong: #39475b;\r\n --accent: #7ea2ff;\r\n --accent-strong: #5f87ee;\r\n --accent-soft: rgba(126, 162, 255, 0.14);\r\n --danger: #ff8f8f;\r\n --danger-soft: rgba(255, 143, 143, 0.12);\r\n --success: #7fd6a6;\r\n --warning: #f1c46f;\r\n --shadow: 0 18px 45px rgba(0, 0, 0, 0.28);\r\n --radius-xl: 22px;\r\n --radius-lg: 16px;\r\n --radius-md: 12px;\r\n --radius-sm: 9px;\r\n --transition: 160ms ease;\r\n --max-width: 1400px;\r\n }\r\n\r\n html[data-theme=\"light\"] {\r\n color-scheme: light;\r\n --bg: #eef2f7;\r\n --surface: #ffffff;\r\n --surface-2: #f6f8fb;\r\n --surface-3: #edf1f6;\r\n --display: #f7f9fc;\r\n --text: #18202b;\r\n --muted: #596678;\r\n --subtle: #7e8996;\r\n --border: #d7dee8;\r\n --border-strong: #c4ceda;\r\n --accent: #315fc9;\r\n --accent-strong: #244aa6;\r\n --accent-soft: rgba(49, 95, 201, 0.10);\r\n --danger: #b84040;\r\n --danger-soft: rgba(184, 64, 64, 0.10);\r\n --success: #24794b;\r\n --warning: #956900;\r\n --shadow: 0 18px 45px rgba(25, 40, 60, 0.12);\r\n }\r\n\r\n \/* =========================================================\r\n 02. RESET & BASE\r\n ========================================================== *\/\r\n *,\r\n *::before,\r\n *::after {\r\n box-sizing: border-box;\r\n }\r\n\r\n html {\r\n font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, \"Segoe UI\", sans-serif;\r\n background: var(--bg);\r\n }\r\n\r\n body {\r\n margin: 0;\r\n min-width: 320px;\r\n min-height: 100%;\r\n background: var(--bg);\r\n color: var(--text);\r\n line-height: 1.5;\r\n -webkit-font-smoothing: antialiased;\r\n }\r\n\r\n button,\r\n input,\r\n select {\r\n font: inherit;\r\n }\r\n\r\n button,\r\n select {\r\n color: inherit;\r\n }\r\n\r\n button {\r\n border: 0;\r\n }\r\n\r\n button:focus-visible,\r\n input:focus-visible,\r\n select:focus-visible {\r\n outline: 3px solid color-mix(in srgb, var(--accent) 58%, transparent);\r\n outline-offset: 2px;\r\n }\r\n\r\n [hidden] {\r\n display: none !important;\r\n }\r\n\r\n ::selection {\r\n background: var(--accent-soft);\r\n }\r\n\r\n \/* =========================================================\r\n 03. APP SHELL\r\n ========================================================== *\/\r\n .app-shell {\r\n width: min(100% - 24px, var(--max-width));\r\n margin: 18px auto 28px;\r\n }\r\n\r\n .app-header {\r\n display: flex;\r\n align-items: center;\r\n justify-content: space-between;\r\n gap: 16px;\r\n margin-bottom: 14px;\r\n }\r\n\r\n .brand-group {\r\n min-width: 0;\r\n }\r\n\r\n .brand-kicker {\r\n margin: 0 0 2px;\r\n color: var(--muted);\r\n font-size: 0.72rem;\r\n font-weight: 700;\r\n letter-spacing: 0.16em;\r\n text-transform: uppercase;\r\n }\r\n\r\n .brand-title {\r\n margin: 0;\r\n font-size: clamp(1.15rem, 2vw, 1.48rem);\r\n line-height: 1.15;\r\n letter-spacing: -0.025em;\r\n }\r\n\r\n .header-actions {\r\n display: flex;\r\n align-items: center;\r\n justify-content: flex-end;\r\n flex-wrap: wrap;\r\n gap: 8px;\r\n }\r\n\r\n .mode-switch,\r\n .segment-control {\r\n display: inline-flex;\r\n align-items: center;\r\n gap: 4px;\r\n padding: 4px;\r\n border: 1px solid var(--border);\r\n border-radius: 12px;\r\n background: var(--surface);\r\n }\r\n\r\n .mode-button,\r\n .segment-button,\r\n .icon-button,\r\n .soft-button {\r\n min-height: 42px;\r\n border-radius: 9px;\r\n background: transparent;\r\n color: var(--muted);\r\n cursor: pointer;\r\n transition: background var(--transition), color var(--transition), transform var(--transition), border-color var(--transition);\r\n }\r\n\r\n .mode-button,\r\n .segment-button {\r\n padding: 0 13px;\r\n font-size: 0.86rem;\r\n font-weight: 750;\r\n }\r\n\r\n .mode-button[aria-pressed=\"true\"],\r\n .segment-button[aria-pressed=\"true\"] {\r\n background: var(--accent-soft);\r\n color: var(--accent);\r\n }\r\n\r\n .icon-button,\r\n .soft-button {\r\n border: 1px solid var(--border);\r\n background: var(--surface);\r\n }\r\n\r\n .icon-button {\r\n width: 44px;\r\n display: inline-grid;\r\n place-items: center;\r\n font-size: 1.05rem;\r\n }\r\n\r\n .soft-button {\r\n padding: 0 13px;\r\n font-size: 0.82rem;\r\n font-weight: 750;\r\n }\r\n\r\n @media (hover: hover) and (pointer: fine) {\r\n .mode-button:hover,\r\n .segment-button:hover,\r\n .icon-button:hover,\r\n .soft-button:hover {\r\n color: var(--text);\r\n background: var(--surface-2);\r\n }\r\n }\r\n\r\n .mode-button:active,\r\n .segment-button:active,\r\n .icon-button:active,\r\n .soft-button:active {\r\n transform: translateY(1px);\r\n }\r\n\r\n \/* =========================================================\r\n 04. LAYOUT\r\n ========================================================== *\/\r\n .workspace {\r\n display: grid;\r\n grid-template-columns: minmax(0, 1fr) 320px;\r\n gap: 14px;\r\n align-items: start;\r\n }\r\n\r\n .calculator-panel,\r\n .history-panel,\r\n .converter-panel,\r\n .settings-panel {\r\n border: 1px solid var(--border);\r\n background: var(--surface);\r\n border-radius: var(--radius-xl);\r\n box-shadow: var(--shadow);\r\n }\r\n\r\n .calculator-panel {\r\n overflow: hidden;\r\n }\r\n\r\n .calculator-body {\r\n padding: 14px;\r\n }\r\n\r\n .history-panel {\r\n padding: 14px;\r\n position: sticky;\r\n top: 14px;\r\n }\r\n\r\n \/* =========================================================\r\n 05. DISPLAY\r\n ========================================================== *\/\r\n .display {\r\n padding: 16px 16px 14px;\r\n background: var(--display);\r\n border-bottom: 1px solid var(--border);\r\n }\r\n\r\n .display-topline {\r\n display: flex;\r\n align-items: center;\r\n justify-content: space-between;\r\n gap: 10px;\r\n margin-bottom: 10px;\r\n }\r\n\r\n .indicators {\r\n display: flex;\r\n flex-wrap: wrap;\r\n gap: 6px;\r\n min-width: 0;\r\n }\r\n\r\n .indicator {\r\n display: inline-flex;\r\n align-items: center;\r\n min-height: 24px;\r\n padding: 0 8px;\r\n border: 1px solid var(--border);\r\n border-radius: 999px;\r\n color: var(--muted);\r\n font-size: 0.68rem;\r\n font-weight: 800;\r\n letter-spacing: 0.04em;\r\n }\r\n\r\n .indicator.is-active {\r\n border-color: color-mix(in srgb, var(--accent) 45%, var(--border));\r\n background: var(--accent-soft);\r\n color: var(--accent);\r\n }\r\n\r\n .display-tools {\r\n display: flex;\r\n gap: 7px;\r\n flex-shrink: 0;\r\n }\r\n\r\n .display-tool {\r\n min-height: 34px;\r\n padding: 0 10px;\r\n border: 1px solid var(--border);\r\n border-radius: 8px;\r\n background: transparent;\r\n color: var(--muted);\r\n cursor: pointer;\r\n font-size: 0.76rem;\r\n font-weight: 800;\r\n }\r\n\r\n .expression-input {\r\n width: 100%;\r\n min-height: 52px;\r\n padding: 6px 0 4px;\r\n border: 0;\r\n background: transparent;\r\n color: var(--text);\r\n font-size: clamp(1.12rem, 2.6vw, 1.58rem);\r\n font-weight: 560;\r\n letter-spacing: 0.005em;\r\n outline: none;\r\n font-variant-numeric: tabular-nums;\r\n }\r\n\r\n .result-row {\r\n display: flex;\r\n align-items: end;\r\n justify-content: space-between;\r\n gap: 12px;\r\n min-height: 62px;\r\n margin-top: 2px;\r\n }\r\n\r\n .result-output {\r\n min-width: 0;\r\n max-width: 100%;\r\n overflow-x: auto;\r\n overflow-y: hidden;\r\n color: var(--text);\r\n font-size: clamp(1.85rem, 5vw, 3rem);\r\n font-weight: 760;\r\n line-height: 1.08;\r\n letter-spacing: -0.035em;\r\n white-space: nowrap;\r\n font-variant-numeric: tabular-nums;\r\n scrollbar-width: thin;\r\n }\r\n\r\n .preview-output {\r\n flex: 0 0 auto;\r\n max-width: 46%;\r\n padding-bottom: 4px;\r\n overflow: hidden;\r\n color: var(--muted);\r\n font-size: 0.9rem;\r\n text-overflow: ellipsis;\r\n white-space: nowrap;\r\n font-variant-numeric: tabular-nums;\r\n }\r\n\r\n .message-line {\r\n min-height: 24px;\r\n margin-top: 6px;\r\n color: var(--muted);\r\n font-size: 0.8rem;\r\n }\r\n\r\n .message-line.is-error {\r\n color: var(--danger);\r\n }\r\n\r\n .message-line.is-success {\r\n color: var(--success);\r\n }\r\n\r\n \/* =========================================================\r\n 06. CALCULATOR CONTROLS\r\n ========================================================== *\/\r\n .control-strip {\r\n display: flex;\r\n align-items: center;\r\n justify-content: space-between;\r\n gap: 10px;\r\n flex-wrap: wrap;\r\n margin-bottom: 10px;\r\n }\r\n\r\n .control-strip-group {\r\n display: flex;\r\n align-items: center;\r\n flex-wrap: wrap;\r\n gap: 7px;\r\n }\r\n\r\n .tiny-button {\r\n min-height: 38px;\r\n min-width: 46px;\r\n padding: 0 11px;\r\n border: 1px solid var(--border);\r\n border-radius: 9px;\r\n background: var(--surface-2);\r\n color: var(--muted);\r\n cursor: pointer;\r\n font-size: 0.74rem;\r\n font-weight: 800;\r\n transition: background var(--transition), color var(--transition), transform var(--transition), border-color var(--transition);\r\n }\r\n\r\n .tiny-button[aria-pressed=\"true\"] {\r\n border-color: color-mix(in srgb, var(--accent) 40%, var(--border));\r\n background: var(--accent-soft);\r\n color: var(--accent);\r\n }\r\n\r\n .tiny-button.is-danger {\r\n color: var(--danger);\r\n }\r\n\r\n @media (hover: hover) and (pointer: fine) {\r\n .tiny-button:hover {\r\n background: var(--surface-3);\r\n color: var(--text);\r\n }\r\n }\r\n\r\n .keypad-layout {\r\n display: grid;\r\n grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.85fr);\r\n gap: 10px;\r\n }\r\n\r\n .scientific-grid,\r\n .numeric-grid {\r\n display: grid;\r\n gap: 8px;\r\n }\r\n\r\n .scientific-grid {\r\n grid-template-columns: repeat(6, minmax(0, 1fr));\r\n }\r\n\r\n .numeric-grid {\r\n grid-template-columns: repeat(4, minmax(0, 1fr));\r\n }\r\n\r\n .calc-key {\r\n position: relative;\r\n min-width: 0;\r\n min-height: 50px;\r\n padding: 8px 6px;\r\n border: 1px solid var(--border);\r\n border-radius: 11px;\r\n background: var(--surface-2);\r\n color: var(--text);\r\n cursor: pointer;\r\n font-size: 0.9rem;\r\n font-weight: 700;\r\n line-height: 1.15;\r\n transition: transform 120ms ease, background var(--transition), border-color var(--transition), color var(--transition);\r\n user-select: none;\r\n -webkit-tap-highlight-color: transparent;\r\n }\r\n\r\n .calc-key.key-number {\r\n background: var(--surface);\r\n font-size: 1rem;\r\n font-weight: 800;\r\n }\r\n\r\n .calc-key.key-operator {\r\n color: var(--accent);\r\n font-size: 1.05rem;\r\n }\r\n\r\n .calc-key.key-function {\r\n color: var(--muted);\r\n font-size: 0.82rem;\r\n }\r\n\r\n .calc-key.key-danger {\r\n color: var(--danger);\r\n background: var(--danger-soft);\r\n }\r\n\r\n .calc-key.key-equals {\r\n border-color: var(--accent);\r\n background: var(--accent);\r\n color: #0b1020;\r\n font-size: 1.08rem;\r\n font-weight: 900;\r\n }\r\n\r\n html[data-theme=\"light\"] .calc-key.key-equals {\r\n color: #ffffff;\r\n }\r\n\r\n .calc-key.key-shifted,\r\n .calc-key.is-flashed {\r\n border-color: color-mix(in srgb, var(--accent) 58%, var(--border));\r\n background: var(--accent-soft);\r\n color: var(--accent);\r\n }\r\n\r\n @media (hover: hover) and (pointer: fine) {\r\n .calc-key:hover {\r\n border-color: var(--border-strong);\r\n background: var(--surface-3);\r\n }\r\n\r\n .calc-key.key-equals:hover {\r\n border-color: var(--accent-strong);\r\n background: var(--accent-strong);\r\n }\r\n }\r\n\r\n .calc-key:active,\r\n .calc-key.is-flashed {\r\n transform: translateY(1px) scale(0.985);\r\n }\r\n\r\n \/* =========================================================\r\n 07. HISTORY\r\n ========================================================== *\/\r\n .panel-heading {\r\n display: flex;\r\n align-items: center;\r\n justify-content: space-between;\r\n gap: 10px;\r\n margin-bottom: 12px;\r\n }\r\n\r\n .panel-title {\r\n margin: 0;\r\n font-size: 0.98rem;\r\n letter-spacing: -0.01em;\r\n }\r\n\r\n .history-list {\r\n display: grid;\r\n gap: 8px;\r\n max-height: 580px;\r\n overflow-y: auto;\r\n padding-right: 2px;\r\n scrollbar-width: thin;\r\n }\r\n\r\n .history-empty {\r\n padding: 22px 12px;\r\n border: 1px dashed var(--border);\r\n border-radius: 12px;\r\n color: var(--muted);\r\n text-align: center;\r\n font-size: 0.84rem;\r\n }\r\n\r\n .history-item {\r\n position: relative;\r\n padding: 11px 38px 10px 11px;\r\n border: 1px solid var(--border);\r\n border-radius: 12px;\r\n background: var(--surface-2);\r\n }\r\n\r\n .history-expression,\r\n .history-result {\r\n width: 100%;\r\n padding: 0;\r\n border: 0;\r\n background: transparent;\r\n text-align: left;\r\n cursor: pointer;\r\n font-variant-numeric: tabular-nums;\r\n }\r\n\r\n .history-expression {\r\n overflow: hidden;\r\n color: var(--muted);\r\n font-size: 0.78rem;\r\n text-overflow: ellipsis;\r\n white-space: nowrap;\r\n }\r\n\r\n .history-result {\r\n margin-top: 3px;\r\n overflow: hidden;\r\n color: var(--text);\r\n font-size: 1rem;\r\n font-weight: 820;\r\n text-overflow: ellipsis;\r\n white-space: nowrap;\r\n }\r\n\r\n .history-time {\r\n display: block;\r\n margin-top: 5px;\r\n color: var(--subtle);\r\n font-size: 0.68rem;\r\n }\r\n\r\n .history-delete {\r\n position: absolute;\r\n top: 8px;\r\n right: 8px;\r\n width: 28px;\r\n height: 28px;\r\n border-radius: 8px;\r\n background: transparent;\r\n color: var(--subtle);\r\n cursor: pointer;\r\n }\r\n\r\n \/* =========================================================\r\n 08. CONVERTER\r\n ========================================================== *\/\r\n .converter-panel {\r\n padding: 18px;\r\n }\r\n\r\n .converter-head {\r\n display: flex;\r\n align-items: start;\r\n justify-content: space-between;\r\n gap: 12px;\r\n margin-bottom: 18px;\r\n }\r\n\r\n .converter-title {\r\n margin: 0 0 3px;\r\n font-size: 1.12rem;\r\n }\r\n\r\n .converter-subtitle {\r\n margin: 0;\r\n color: var(--muted);\r\n font-size: 0.82rem;\r\n }\r\n\r\n .converter-grid {\r\n display: grid;\r\n grid-template-columns: repeat(2, minmax(0, 1fr));\r\n gap: 14px;\r\n }\r\n\r\n .converter-card {\r\n padding: 14px;\r\n border: 1px solid var(--border);\r\n border-radius: var(--radius-lg);\r\n background: var(--surface-2);\r\n }\r\n\r\n .field-label {\r\n display: block;\r\n margin-bottom: 6px;\r\n color: var(--muted);\r\n font-size: 0.74rem;\r\n font-weight: 780;\r\n letter-spacing: 0.03em;\r\n text-transform: uppercase;\r\n }\r\n\r\n .field-control {\r\n width: 100%;\r\n min-height: 48px;\r\n padding: 0 12px;\r\n border: 1px solid var(--border);\r\n border-radius: 10px;\r\n background: var(--surface);\r\n color: var(--text);\r\n outline: none;\r\n }\r\n\r\n .field-stack {\r\n display: grid;\r\n gap: 12px;\r\n }\r\n\r\n .converter-result {\r\n display: flex;\r\n align-items: end;\r\n min-height: 48px;\r\n padding: 8px 12px;\r\n border: 1px solid var(--border);\r\n border-radius: 10px;\r\n background: var(--display);\r\n color: var(--text);\r\n font-size: 1.1rem;\r\n font-weight: 820;\r\n font-variant-numeric: tabular-nums;\r\n overflow-wrap: anywhere;\r\n }\r\n\r\n \/* =========================================================\r\n 09. SETTINGS DIALOG\r\n ========================================================== *\/\r\n .settings-backdrop {\r\n position: fixed;\r\n inset: 0;\r\n z-index: 40;\r\n display: grid;\r\n place-items: center;\r\n padding: 18px;\r\n background: rgba(3, 7, 12, 0.66);\r\n }\r\n\r\n .settings-panel {\r\n width: min(100%, 520px);\r\n max-height: min(720px, calc(100vh - 36px));\r\n overflow-y: auto;\r\n padding: 18px;\r\n }\r\n\r\n .settings-list {\r\n display: grid;\r\n gap: 14px;\r\n }\r\n\r\n .setting-row {\r\n display: grid;\r\n grid-template-columns: minmax(0, 1fr) minmax(160px, 0.62fr);\r\n gap: 14px;\r\n align-items: center;\r\n }\r\n\r\n .setting-copy strong {\r\n display: block;\r\n font-size: 0.88rem;\r\n }\r\n\r\n .setting-copy span {\r\n display: block;\r\n margin-top: 2px;\r\n color: var(--muted);\r\n font-size: 0.76rem;\r\n }\r\n\r\n .settings-footer {\r\n display: flex;\r\n justify-content: flex-end;\r\n gap: 8px;\r\n margin-top: 18px;\r\n }\r\n\r\n .shortcut-list {\r\n display: grid;\r\n grid-template-columns: repeat(2, minmax(0, 1fr));\r\n gap: 7px 12px;\r\n padding: 12px;\r\n border: 1px solid var(--border);\r\n border-radius: 12px;\r\n background: var(--surface-2);\r\n }\r\n\r\n .shortcut-item {\r\n display: flex;\r\n justify-content: space-between;\r\n gap: 10px;\r\n color: var(--muted);\r\n font-size: 0.76rem;\r\n }\r\n\r\n .shortcut-item kbd {\r\n min-width: 32px;\r\n padding: 2px 7px;\r\n border: 1px solid var(--border-strong);\r\n border-radius: 6px;\r\n background: var(--surface);\r\n color: var(--text);\r\n text-align: center;\r\n font: inherit;\r\n font-weight: 780;\r\n }\r\n\r\n \/* =========================================================\r\n 10. MOBILE HISTORY DRAWER\r\n ========================================================== *\/\r\n .mobile-history-toggle {\r\n display: none;\r\n }\r\n\r\n .mobile-history-backdrop {\r\n display: none;\r\n }\r\n\r\n \/* =========================================================\r\n 11. RESPONSIVE\r\n ========================================================== *\/\r\n @media (max-width: 1080px) {\r\n .workspace {\r\n grid-template-columns: minmax(0, 1fr) 286px;\r\n }\r\n\r\n .keypad-layout {\r\n grid-template-columns: 1fr;\r\n }\r\n\r\n .scientific-grid {\r\n grid-template-columns: repeat(6, minmax(0, 1fr));\r\n }\r\n }\r\n\r\n @media (max-width: 820px) {\r\n .app-shell {\r\n width: min(100% - 16px, var(--max-width));\r\n margin-top: 8px;\r\n }\r\n\r\n .app-header {\r\n align-items: flex-start;\r\n }\r\n\r\n .workspace {\r\n grid-template-columns: 1fr;\r\n }\r\n\r\n .history-panel {\r\n position: fixed;\r\n top: 0;\r\n right: 0;\r\n z-index: 31;\r\n width: min(88vw, 360px);\r\n height: 100%;\r\n border-radius: 20px 0 0 20px;\r\n transform: translateX(104%);\r\n transition: transform var(--transition);\r\n }\r\n\r\n .history-panel.is-open {\r\n transform: translateX(0);\r\n }\r\n\r\n .mobile-history-toggle {\r\n display: inline-grid;\r\n }\r\n\r\n .mobile-history-backdrop {\r\n position: fixed;\r\n inset: 0;\r\n z-index: 30;\r\n display: block;\r\n background: rgba(3, 7, 12, 0.56);\r\n }\r\n\r\n .history-list {\r\n max-height: calc(100vh - 94px);\r\n }\r\n }\r\n\r\n @media (max-width: 640px) {\r\n .app-header {\r\n gap: 10px;\r\n }\r\n\r\n .brand-kicker {\r\n display: none;\r\n }\r\n\r\n .header-actions {\r\n gap: 6px;\r\n }\r\n\r\n .mode-switch {\r\n order: 3;\r\n width: 100%;\r\n }\r\n\r\n .mode-button {\r\n flex: 1 1 0;\r\n }\r\n\r\n .calculator-body,\r\n .display {\r\n padding-left: 10px;\r\n padding-right: 10px;\r\n }\r\n\r\n .display-topline {\r\n align-items: flex-start;\r\n }\r\n\r\n .preview-output {\r\n max-width: 42%;\r\n }\r\n\r\n .scientific-grid {\r\n grid-template-columns: repeat(4, minmax(0, 1fr));\r\n }\r\n\r\n .calc-key {\r\n min-height: 48px;\r\n }\r\n\r\n .converter-grid,\r\n .setting-row {\r\n grid-template-columns: 1fr;\r\n }\r\n\r\n .shortcut-list {\r\n grid-template-columns: 1fr;\r\n }\r\n }\r\n\r\n @media (max-width: 390px) {\r\n .app-shell {\r\n width: min(100% - 10px, var(--max-width));\r\n }\r\n\r\n .brand-title {\r\n font-size: 1.05rem;\r\n }\r\n\r\n .icon-button {\r\n width: 42px;\r\n }\r\n\r\n .scientific-grid {\r\n grid-template-columns: repeat(3, minmax(0, 1fr));\r\n }\r\n\r\n .numeric-grid {\r\n gap: 7px;\r\n }\r\n\r\n .calc-key {\r\n padding-inline: 4px;\r\n }\r\n }\r\n\r\n @media (prefers-reduced-motion: reduce) {\r\n *,\r\n *::before,\r\n *::after {\r\n scroll-behavior: auto !important;\r\n transition-duration: 0.01ms !important;\r\n animation-duration: 0.01ms !important;\r\n }\r\n }\r\n <\/style>\r\n<\/head>\r\n<body>\r\n <main class=\"app-shell\" id=\"appRoot\">\r\n \r\n <header class=\"app-header\">\r\n <div class=\"brand-group\">\r\n <p class=\"brand-kicker\">Precision workspace<\/p>\r\n <h1 class=\"brand-title\">NOVA Scientific<\/h1>\r\n <\/div>\r\n\r\n <div class=\"header-actions\">\r\n <div class=\"mode-switch\" aria-label=\"Application mode\">\r\n <button class=\"mode-button\" id=\"scientificModeButton\" type=\"button\" aria-pressed=\"true\">Scientific<\/button>\r\n <button class=\"mode-button\" id=\"converterModeButton\" type=\"button\" aria-pressed=\"false\">Converter<\/button>\r\n <\/div>\r\n\r\n <button class=\"icon-button mobile-history-toggle\" id=\"mobileHistoryButton\" type=\"button\" aria-label=\"Open calculation history\" title=\"History\">\u2315<\/button>\r\n <button class=\"icon-button\" id=\"themeButton\" type=\"button\" aria-label=\"Toggle color theme\" title=\"Toggle theme\">\u25d0<\/button>\r\n <button class=\"icon-button\" id=\"settingsButton\" type=\"button\" aria-label=\"Open settings\" title=\"Settings\">\u2699<\/button>\r\n <\/div>\r\n <\/header>\r\n\r\n \r\n <section class=\"workspace\" id=\"scientificWorkspace\" aria-label=\"Scientific calculator workspace\">\r\n <section class=\"calculator-panel\" aria-label=\"Scientific calculator\">\r\n \r\n <div class=\"display\">\r\n <div class=\"display-topline\">\r\n <div class=\"indicators\" aria-label=\"Calculator status\">\r\n <span class=\"indicator is-active\" id=\"angleIndicator\">DEG<\/span>\r\n <span class=\"indicator\" id=\"memoryIndicator\">M<\/span>\r\n <span class=\"indicator\" id=\"shiftIndicator\">2nd<\/span>\r\n <span class=\"indicator is-active\" id=\"formatIndicator\">NORMAL<\/span>\r\n <\/div>\r\n\r\n <div class=\"display-tools\">\r\n <button class=\"display-tool\" id=\"fractionButton\" type=\"button\" title=\"Convert result to fraction\">a\/b<\/button>\r\n <button class=\"display-tool\" id=\"copyButton\" type=\"button\" title=\"Copy result\">Copy<\/button>\r\n <\/div>\r\n <\/div>\r\n\r\n <label for=\"expressionInput\" class=\"field-label\" style=\"position:absolute;left:-9999px;\">Expression<\/label>\r\n <input\r\n class=\"expression-input\"\r\n id=\"expressionInput\"\r\n type=\"text\"\r\n inputmode=\"text\"\r\n autocomplete=\"off\"\r\n autocapitalize=\"off\"\r\n spellcheck=\"false\"\r\n aria-describedby=\"messageLine\"\r\n placeholder=\"Enter an expression\u2026\"\r\n >\r\n\r\n <div class=\"result-row\">\r\n <output class=\"result-output\" id=\"resultOutput\" aria-live=\"polite\">0<\/output>\r\n <div class=\"preview-output\" id=\"previewOutput\" aria-live=\"off\"><\/div>\r\n <\/div>\r\n\r\n <div class=\"message-line\" id=\"messageLine\" aria-live=\"polite\"><\/div>\r\n <\/div>\r\n\r\n \r\n <div class=\"calculator-body\">\r\n <div class=\"control-strip\">\r\n <div class=\"control-strip-group\" aria-label=\"Angle mode\">\r\n <button class=\"tiny-button\" type=\"button\" data-angle=\"DEG\" aria-pressed=\"true\">DEG<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-angle=\"RAD\" aria-pressed=\"false\">RAD<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-angle=\"GRAD\" aria-pressed=\"false\">GRAD<\/button>\r\n <\/div>\r\n\r\n <div class=\"control-strip-group\" aria-label=\"Memory controls\">\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-clear\">MC<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-recall\">MR<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-add\">M+<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-subtract\">M\u2212<\/button>\r\n <button class=\"tiny-button\" type=\"button\" data-action=\"memory-store\">MS<\/button>\r\n <\/div>\r\n <\/div>\r\n\r\n <div class=\"keypad-layout\">\r\n \r\n <div class=\"scientific-grid\" id=\"scientificGrid\" aria-label=\"Scientific functions\">\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"shift\" id=\"shiftButton\">2nd<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"(\">(<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\")\">)<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"smart-parenthesis\">( )<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"pi\">\u03c0<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"e\">e<\/button>\r\n\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"sin\" data-shift-label=\"sin\u207b\u00b9\" data-normal-insert=\"sin(\" data-shift-insert=\"asin(\" data-insert=\"sin(\">sin<\/button>\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"cos\" data-shift-label=\"cos\u207b\u00b9\" data-normal-insert=\"cos(\" data-shift-insert=\"acos(\" data-insert=\"cos(\">cos<\/button>\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"tan\" data-shift-label=\"tan\u207b\u00b9\" data-normal-insert=\"tan(\" data-shift-insert=\"atan(\" data-insert=\"tan(\">tan<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"sinh(\">sinh<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"cosh(\">cosh<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"tanh(\">tanh<\/button>\r\n\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"x\u00b2\" data-shift-label=\"\u221ax\" data-normal-action=\"square\" data-shift-insert=\"sqrt(\" data-action=\"square\">x\u00b2<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"cube\">x\u00b3<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"^\">x\u02b8<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"sqrt(\">\u221ax<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"cbrt(\">\u221bx<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"root(\">\u02b8\u221ax<\/button>\r\n\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"10\u02e3\" data-shift-label=\"log\" data-normal-insert=\"10^(\" data-shift-insert=\"log(\" data-insert=\"10^(\">10\u02e3<\/button>\r\n <button class=\"calc-key key-function shiftable\" type=\"button\" data-normal-label=\"e\u02e3\" data-shift-label=\"ln\" data-normal-insert=\"e^(\" data-shift-insert=\"ln(\" data-insert=\"e^(\">e\u02e3<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"2^(\">2\u02e3<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"log(\">log<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"ln(\">ln<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"log2(\">log\u2082<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"abs(\">|x|<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"!\">x!<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"reciprocal\">1\/x<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"floor(\">floor<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"ceil(\">ceil<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"round(\">round<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"ncr(\">nCr<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"npr(\">nPr<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"gcd(\">gcd<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"lcm(\">lcm<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"mod(\">mod<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"random\">RAND<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"min(\">min<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"max(\">max<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"trunc(\">trunc<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"sign(\">sign<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"phi\">\u03c6<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"E\">EXP<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"logb(\">log\u1d66<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"randbetween(\">RND(a,b)<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"atanh(\">atanh<\/button>\r\n <\/div>\r\n\r\n \r\n <div class=\"numeric-grid\" id=\"numericGrid\" aria-label=\"Basic calculator keypad\">\r\n <button class=\"calc-key key-danger\" type=\"button\" data-action=\"clear\">AC<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"backspace\">\u232b<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"%\">%<\/button>\r\n <button class=\"calc-key key-operator\" type=\"button\" data-insert=\"\u00f7\">\u00f7<\/button>\r\n\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"7\">7<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"8\">8<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"9\">9<\/button>\r\n <button class=\"calc-key key-operator\" type=\"button\" data-insert=\"\u00d7\">\u00d7<\/button>\r\n\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"4\">4<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"5\">5<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"6\">6<\/button>\r\n <button class=\"calc-key key-operator\" type=\"button\" data-insert=\"-\">\u2212<\/button>\r\n\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"1\">1<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"2\">2<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"3\">3<\/button>\r\n <button class=\"calc-key key-operator\" type=\"button\" data-insert=\"+\">+<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-action=\"toggle-sign\">\u00b1<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\"0\">0<\/button>\r\n <button class=\"calc-key key-number\" type=\"button\" data-insert=\".\">.<\/button>\r\n <button class=\"calc-key key-equals\" type=\"button\" data-action=\"evaluate\">=<\/button>\r\n\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"ans\">ANS<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\",\">,<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"asinh(\">asinh<\/button>\r\n <button class=\"calc-key key-function\" type=\"button\" data-insert=\"acosh(\">acosh<\/button>\r\n <\/div>\r\n <\/div>\r\n <\/div>\r\n <\/section>\r\n\r\n \r\n <aside class=\"history-panel\" id=\"historyPanel\" aria-label=\"Calculation history\">\r\n <div class=\"panel-heading\">\r\n <h2 class=\"panel-title\">History<\/h2>\r\n <button class=\"soft-button\" id=\"clearHistoryButton\" type=\"button\">Clear<\/button>\r\n <\/div>\r\n <div class=\"history-list\" id=\"historyList\"><\/div>\r\n <\/aside>\r\n <\/section>\r\n\r\n \r\n <section class=\"converter-panel\" id=\"converterWorkspace\" aria-label=\"Unit converter\" hidden>\r\n <div class=\"converter-head\">\r\n <div>\r\n <h2 class=\"converter-title\">Unit converter<\/h2>\r\n <p class=\"converter-subtitle\">Offline conversions for common scientific and everyday units.<\/p>\r\n <\/div>\r\n <span class=\"indicator is-active\">LOCAL<\/span>\r\n <\/div>\r\n\r\n <div class=\"converter-grid\">\r\n <div class=\"converter-card field-stack\">\r\n <div>\r\n <label class=\"field-label\" for=\"converterCategory\">Category<\/label>\r\n <select class=\"field-control\" id=\"converterCategory\"><\/select>\r\n <\/div>\r\n <div>\r\n <label class=\"field-label\" for=\"converterValue\">Value<\/label>\r\n <input class=\"field-control\" id=\"converterValue\" type=\"number\" inputmode=\"decimal\" step=\"any\" value=\"1\">\r\n <\/div>\r\n <\/div>\r\n\r\n <div class=\"converter-card field-stack\">\r\n <div>\r\n <label class=\"field-label\" for=\"converterFrom\">From<\/label>\r\n <select class=\"field-control\" id=\"converterFrom\"><\/select>\r\n <\/div>\r\n <div>\r\n <label class=\"field-label\" for=\"converterTo\">To<\/label>\r\n <select class=\"field-control\" id=\"converterTo\"><\/select>\r\n <\/div>\r\n <\/div>\r\n\r\n <div class=\"converter-card field-stack\">\r\n <div>\r\n <span class=\"field-label\">Converted result<\/span>\r\n <output class=\"converter-result\" id=\"converterResult\" aria-live=\"polite\">1<\/output>\r\n <\/div>\r\n <button class=\"soft-button\" id=\"swapUnitsButton\" type=\"button\">Swap units<\/button>\r\n <\/div>\r\n\r\n <div class=\"converter-card field-stack\">\r\n <div>\r\n <span class=\"field-label\">Formula<\/span>\r\n <div class=\"converter-result\" id=\"converterFormula\" style=\"font-size:0.88rem;font-weight:650;color:var(--muted);\">Direct scale conversion<\/div>\r\n <\/div>\r\n <\/div>\r\n <\/div>\r\n <\/section>\r\n <\/main>\r\n\r\n \r\n <button class=\"mobile-history-backdrop\" id=\"mobileHistoryBackdrop\" type=\"button\" aria-label=\"Close history\" hidden><\/button>\r\n\r\n \r\n <div class=\"settings-backdrop\" id=\"settingsBackdrop\" hidden>\r\n <section class=\"settings-panel\" role=\"dialog\" aria-modal=\"true\" aria-labelledby=\"settingsTitle\">\r\n <div class=\"panel-heading\">\r\n <h2 class=\"panel-title\" id=\"settingsTitle\">Calculator settings<\/h2>\r\n <button class=\"icon-button\" id=\"closeSettingsButton\" type=\"button\" aria-label=\"Close settings\">\u00d7<\/button>\r\n <\/div>\r\n\r\n <div class=\"settings-list\">\r\n <div class=\"setting-row\">\r\n <div class=\"setting-copy\">\r\n <strong>Theme<\/strong>\r\n <span>Choose light or dark appearance.<\/span>\r\n <\/div>\r\n <select class=\"field-control\" id=\"themeSelect\">\r\n <option value=\"dark\">Dark<\/option>\r\n <option value=\"light\">Light<\/option>\r\n <\/select>\r\n <\/div>\r\n\r\n <div class=\"setting-row\">\r\n <div class=\"setting-copy\">\r\n <strong>Number format<\/strong>\r\n <span>Normal, scientific, or engineering notation.<\/span>\r\n <\/div>\r\n <select class=\"field-control\" id=\"formatSelect\">\r\n <option value=\"normal\">Normal<\/option>\r\n <option value=\"scientific\">Scientific<\/option>\r\n <option value=\"engineering\">Engineering<\/option>\r\n <\/select>\r\n <\/div>\r\n\r\n <div class=\"setting-row\">\r\n <div class=\"setting-copy\">\r\n <strong>Precision<\/strong>\r\n <span>Display precision only; internal calculations keep full floating-point precision.<\/span>\r\n <\/div>\r\n <select class=\"field-control\" id=\"precisionSelect\">\r\n <option value=\"auto\">Auto<\/option>\r\n <option value=\"4\">4 decimals<\/option>\r\n <option value=\"6\">6 decimals<\/option>\r\n <option value=\"8\">8 decimals<\/option>\r\n <option value=\"10\">10 decimals<\/option>\r\n <option value=\"12\">12 decimals<\/option>\r\n <\/select>\r\n <\/div>\r\n\r\n <div class=\"setting-row\">\r\n <div class=\"setting-copy\">\r\n <strong>History persistence<\/strong>\r\n <span>Keep recent calculations after closing the browser.<\/span>\r\n <\/div>\r\n <select class=\"field-control\" id=\"historyPersistenceSelect\">\r\n <option value=\"on\">On<\/option>\r\n <option value=\"off\">Off<\/option>\r\n <\/select>\r\n <\/div>\r\n\r\n <div>\r\n <span class=\"field-label\">Keyboard shortcuts<\/span>\r\n <div class=\"shortcut-list\">\r\n <div class=\"shortcut-item\"><span>Calculate<\/span><kbd>Enter<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Clear<\/span><kbd>Esc<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Delete<\/span><kbd>\u232b<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Power<\/span><kbd>^<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Multiply<\/span><kbd>*<\/kbd><\/div>\r\n <div class=\"shortcut-item\"><span>Divide<\/span><kbd>\/<\/kbd><\/div>\r\n <\/div>\r\n <\/div>\r\n <\/div>\r\n\r\n <div class=\"settings-footer\">\r\n <button class=\"soft-button\" id=\"resetSettingsButton\" type=\"button\">Reset settings<\/button>\r\n <button class=\"soft-button\" id=\"doneSettingsButton\" type=\"button\">Done<\/button>\r\n <\/div>\r\n <\/section>\r\n <\/div>\r\n\r\n <script>\r\n \"use strict\";\r\n\r\n \/* =========================================================\r\n 01. CONSTANTS & APPLICATION STATE\r\n ========================================================== *\/\r\n const STORAGE_KEYS = {\r\n theme: \"nova.theme\",\r\n angle: \"nova.angle\",\r\n precision: \"nova.precision\",\r\n format: \"nova.format\",\r\n history: \"nova.history\",\r\n historyPersistence: \"nova.historyPersistence\"\r\n };\r\n\r\n const MAX_HISTORY = 60;\r\n const MAX_FACTORIAL = 170;\r\n const GOLDEN_RATIO = (1 + Math.sqrt(5)) \/ 2;\r\n\r\n const state = {\r\n expression: \"\",\r\n result: 0,\r\n previousAnswer: 0,\r\n memory: 0,\r\n angleMode: \"DEG\",\r\n secondMode: false,\r\n theme: \"dark\",\r\n numberFormat: \"normal\",\r\n precision: \"auto\",\r\n historyPersistence: true,\r\n history: [],\r\n justEvaluated: false,\r\n lastEvaluation: null,\r\n currentMode: \"scientific\"\r\n };\r\n\r\n \/* =========================================================\r\n 02. DOM CACHE\r\n ========================================================== *\/\r\n const dom = {\r\n html: document.documentElement,\r\n expressionInput: document.getElementById(\"expressionInput\"),\r\n resultOutput: document.getElementById(\"resultOutput\"),\r\n previewOutput: document.getElementById(\"previewOutput\"),\r\n messageLine: document.getElementById(\"messageLine\"),\r\n angleIndicator: document.getElementById(\"angleIndicator\"),\r\n memoryIndicator: document.getElementById(\"memoryIndicator\"),\r\n shiftIndicator: document.getElementById(\"shiftIndicator\"),\r\n formatIndicator: document.getElementById(\"formatIndicator\"),\r\n scientificWorkspace: document.getElementById(\"scientificWorkspace\"),\r\n converterWorkspace: document.getElementById(\"converterWorkspace\"),\r\n scientificModeButton: document.getElementById(\"scientificModeButton\"),\r\n converterModeButton: document.getElementById(\"converterModeButton\"),\r\n themeButton: document.getElementById(\"themeButton\"),\r\n settingsButton: document.getElementById(\"settingsButton\"),\r\n copyButton: document.getElementById(\"copyButton\"),\r\n fractionButton: document.getElementById(\"fractionButton\"),\r\n shiftButton: document.getElementById(\"shiftButton\"),\r\n historyList: document.getElementById(\"historyList\"),\r\n historyPanel: document.getElementById(\"historyPanel\"),\r\n clearHistoryButton: document.getElementById(\"clearHistoryButton\"),\r\n mobileHistoryButton: document.getElementById(\"mobileHistoryButton\"),\r\n mobileHistoryBackdrop: document.getElementById(\"mobileHistoryBackdrop\"),\r\n settingsBackdrop: document.getElementById(\"settingsBackdrop\"),\r\n closeSettingsButton: document.getElementById(\"closeSettingsButton\"),\r\n doneSettingsButton: document.getElementById(\"doneSettingsButton\"),\r\n resetSettingsButton: document.getElementById(\"resetSettingsButton\"),\r\n themeSelect: document.getElementById(\"themeSelect\"),\r\n formatSelect: document.getElementById(\"formatSelect\"),\r\n precisionSelect: document.getElementById(\"precisionSelect\"),\r\n historyPersistenceSelect: document.getElementById(\"historyPersistenceSelect\"),\r\n converterCategory: document.getElementById(\"converterCategory\"),\r\n converterValue: document.getElementById(\"converterValue\"),\r\n converterFrom: document.getElementById(\"converterFrom\"),\r\n converterTo: document.getElementById(\"converterTo\"),\r\n converterResult: document.getElementById(\"converterResult\"),\r\n converterFormula: document.getElementById(\"converterFormula\"),\r\n swapUnitsButton: document.getElementById(\"swapUnitsButton\")\r\n };\r\n\r\n \/* =========================================================\r\n 03. UTILITY HELPERS\r\n ========================================================== *\/\r\n function clamp(value, min, max) {\r\n return Math.min(Math.max(value, min), max);\r\n }\r\n\r\n function nearlyInteger(value) {\r\n return Math.abs(value - Math.round(value)) < 1e-12;\r\n }\r\n\r\n function isFiniteNumber(value) {\r\n return typeof value === \"number\" && Number.isFinite(value);\r\n }\r\n\r\n function safeStorageGet(key) {\r\n try {\r\n return localStorage.getItem(key);\r\n } catch {\r\n return null;\r\n }\r\n }\r\n\r\n function safeStorageSet(key, value) {\r\n try {\r\n localStorage.setItem(key, value);\r\n return true;\r\n } catch {\r\n return false;\r\n }\r\n }\r\n\r\n function safeStorageRemove(key) {\r\n try {\r\n localStorage.removeItem(key);\r\n } catch {\r\n \/\/ Persistence is optional; silently continue.\r\n }\r\n }\r\n\r\n function normalizeNegativeZero(value) {\r\n return Object.is(value, -0) ? 0 : value;\r\n }\r\n\r\n function roundFloatingNoise(value) {\r\n if (!isFiniteNumber(value)) return value;\r\n if (value === 0) return 0;\r\n const magnitude = Math.abs(value);\r\n if (magnitude >= 1e15 || magnitude < 1e-12) return value;\r\n return Number.parseFloat(value.toPrecision(15));\r\n }\r\n\r\n function showMessage(message = \"\", type = \"neutral\") {\r\n dom.messageLine.textContent = message;\r\n dom.messageLine.classList.toggle(\"is-error\", type === \"error\");\r\n dom.messageLine.classList.toggle(\"is-success\", type === \"success\");\r\n }\r\n\r\n function clearMessage() {\r\n showMessage(\"\");\r\n }\r\n\r\n \/* =========================================================\r\n 04. MATHEMATICAL DOMAIN HELPERS\r\n ========================================================== *\/\r\n function toRadians(value) {\r\n if (state.angleMode === \"DEG\") return value * Math.PI \/ 180;\r\n if (state.angleMode === \"GRAD\") return value * Math.PI \/ 200;\r\n return value;\r\n }\r\n\r\n function fromRadians(value) {\r\n if (state.angleMode === \"DEG\") return value * 180 \/ Math.PI;\r\n if (state.angleMode === \"GRAD\") return value * 200 \/ Math.PI;\r\n return value;\r\n }\r\n\r\n function factorial(value) {\r\n if (!nearlyInteger(value) || value < 0) {\r\n throw new CalcError(\"Factorial requires a non-negative integer\");\r\n }\r\n if (value > MAX_FACTORIAL) {\r\n throw new CalcError(\"Factorial is too large for this calculator\");\r\n }\r\n let result = 1;\r\n for (let i = 2; i <= value; i += 1) result *= i;\r\n return result;\r\n }\r\n\r\n function integerGcd(a, b) {\r\n if (!nearlyInteger(a) || !nearlyInteger(b)) {\r\n throw new CalcError(\"gcd requires integer arguments\");\r\n }\r\n a = Math.abs(Math.trunc(a));\r\n b = Math.abs(Math.trunc(b));\r\n while (b !== 0) {\r\n [a, b] = [b, a % b];\r\n }\r\n return a;\r\n }\r\n\r\n function integerLcm(a, b) {\r\n if (!nearlyInteger(a) || !nearlyInteger(b)) {\r\n throw new CalcError(\"lcm requires integer arguments\");\r\n }\r\n if (a === 0 || b === 0) return 0;\r\n return Math.abs((a \/ integerGcd(a, b)) * b);\r\n }\r\n\r\n function combination(n, r) {\r\n if (!nearlyInteger(n) || !nearlyInteger(r) || n < 0 || r < 0 || r > n) {\r\n throw new CalcError(\"nCr requires integers with 0 \u2264 r \u2264 n\");\r\n }\r\n r = Math.min(r, n - r);\r\n let result = 1;\r\n for (let i = 1; i <= r; i += 1) {\r\n result = result * (n - r + i) \/ i;\r\n }\r\n return result;\r\n }\r\n\r\n function permutation(n, r) {\r\n if (!nearlyInteger(n) || !nearlyInteger(r) || n < 0 || r < 0 || r > n) {\r\n throw new CalcError(\"nPr requires integers with 0 \u2264 r \u2264 n\");\r\n }\r\n let result = 1;\r\n for (let i = 0; i < r; i += 1) result *= (n - i);\r\n return result;\r\n }\r\n\r\n \/* =========================================================\r\n 05. CALCULATOR ERROR TYPE\r\n ========================================================== *\/\r\n class CalcError extends Error {\r\n constructor(message) {\r\n super(message);\r\n this.name = \"CalcError\";\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 06. TOKENIZER\r\n ========================================================== *\/\r\n const FUNCTION_NAMES = new Set([\r\n \"sin\", \"cos\", \"tan\", \"asin\", \"acos\", \"atan\",\r\n \"sinh\", \"cosh\", \"tanh\", \"asinh\", \"acosh\", \"atanh\",\r\n \"log\", \"ln\", \"log2\", \"logb\", \"sqrt\", \"cbrt\", \"root\",\r\n \"abs\", \"floor\", \"ceil\", \"round\", \"trunc\", \"sign\",\r\n \"min\", \"max\", \"gcd\", \"lcm\", \"ncr\", \"npr\", \"mod\",\r\n \"randbetween\"\r\n ]);\r\n\r\n const CONSTANT_NAMES = new Set([\"pi\", \"e\", \"phi\", \"ans\"]);\r\n\r\n function normalizeExpressionSource(source) {\r\n return source\r\n .replace(\/\u00d7\/g, \"*\")\r\n .replace(\/\u00f7\/g, \"\/\")\r\n .replace(\/[\u2212\u2013\u2014]\/g, \"-\")\r\n .replace(\/\u03c0\/g, \"pi\")\r\n .replace(\/\u03c6\/g, \"phi\")\r\n .replace(\/\u221a\/g, \"sqrt\")\r\n .trim();\r\n }\r\n\r\n function tokenize(source) {\r\n const input = normalizeExpressionSource(source);\r\n const tokens = [];\r\n let index = 0;\r\n\r\n while (index < input.length) {\r\n const char = input[index];\r\n\r\n if (\/\\s\/.test(char)) {\r\n index += 1;\r\n continue;\r\n }\r\n\r\n if (\/\\d|\\.\/.test(char)) {\r\n const start = index;\r\n let sawDot = false;\r\n\r\n if (char === \".\") sawDot = true;\r\n index += 1;\r\n\r\n while (index < input.length) {\r\n const next = input[index];\r\n if (\/\\d\/.test(next)) {\r\n index += 1;\r\n continue;\r\n }\r\n if (next === \".\" && !sawDot) {\r\n sawDot = true;\r\n index += 1;\r\n continue;\r\n }\r\n break;\r\n }\r\n\r\n if (input[index] === \"e\" || input[index] === \"E\") {\r\n let exponentIndex = index + 1;\r\n if (input[exponentIndex] === \"+\" || input[exponentIndex] === \"-\") exponentIndex += 1;\r\n const digitsStart = exponentIndex;\r\n while (\/\\d\/.test(input[exponentIndex] || \"\")) exponentIndex += 1;\r\n if (exponentIndex > digitsStart) index = exponentIndex;\r\n }\r\n\r\n const raw = input.slice(start, index);\r\n if (!\/^(?:\\d+\\.?\\d*|\\.\\d+)(?:[eE][+-]?\\d+)?$\/.test(raw)) {\r\n throw new CalcError(\"Invalid number format\");\r\n }\r\n tokens.push({ type: \"number\", value: Number(raw), raw });\r\n continue;\r\n }\r\n\r\n if (\/[A-Za-z]\/.test(char)) {\r\n const start = index;\r\n index += 1;\r\n while (\/[A-Za-z0-9_]\/.test(input[index] || \"\")) index += 1;\r\n const name = input.slice(start, index).toLowerCase();\r\n tokens.push({ type: \"identifier\", value: name });\r\n continue;\r\n }\r\n\r\n if (\"+-*\/^!%,()\".includes(char)) {\r\n if (char === \"(\") tokens.push({ type: \"lparen\", value: char });\r\n else if (char === \")\") tokens.push({ type: \"rparen\", value: char });\r\n else if (char === \",\") tokens.push({ type: \"comma\", value: char });\r\n else tokens.push({ type: \"operator\", value: char });\r\n index += 1;\r\n continue;\r\n }\r\n\r\n throw new CalcError(`Unsupported symbol: ${char}`);\r\n }\r\n\r\n return insertImplicitMultiplication(tokens);\r\n }\r\n\r\n function canEndImplicitMultiplication(token) {\r\n if (!token) return false;\r\n return token.type === \"number\" ||\r\n token.type === \"rparen\" ||\r\n (token.type === \"identifier\" && CONSTANT_NAMES.has(token.value)) ||\r\n (token.type === \"operator\" && (token.value === \"!\" || token.value === \"%\"));\r\n }\r\n\r\n function canStartImplicitMultiplication(token) {\r\n if (!token) return false;\r\n if (token.type === \"number\" || token.type === \"lparen\") return true;\r\n if (token.type === \"identifier\") return true;\r\n return false;\r\n }\r\n\r\n function insertImplicitMultiplication(tokens) {\r\n const output = [];\r\n\r\n for (let i = 0; i < tokens.length; i += 1) {\r\n const current = tokens[i];\r\n const previous = output[output.length - 1];\r\n\r\n const previousIsFunction = previous?.type === \"identifier\" && FUNCTION_NAMES.has(previous.value);\r\n const currentIsLParen = current.type === \"lparen\";\r\n\r\n if (\r\n previous &&\r\n canEndImplicitMultiplication(previous) &&\r\n canStartImplicitMultiplication(current) &&\r\n !(previousIsFunction && currentIsLParen)\r\n ) {\r\n output.push({ type: \"operator\", value: \"*\", implicit: true });\r\n }\r\n\r\n output.push(current);\r\n }\r\n\r\n return output;\r\n }\r\n\r\n \/* =========================================================\r\n 07. RECURSIVE-DESCENT EXPRESSION PARSER\r\n ========================================================== *\/\r\n class Parser {\r\n constructor(tokens) {\r\n this.tokens = tokens;\r\n this.position = 0;\r\n }\r\n\r\n peek(offset = 0) {\r\n return this.tokens[this.position + offset] || null;\r\n }\r\n\r\n consume() {\r\n return this.tokens[this.position++] || null;\r\n }\r\n\r\n match(type, value = null) {\r\n const token = this.peek();\r\n if (!token || token.type !== type) return false;\r\n if (value !== null && token.value !== value) return false;\r\n this.position += 1;\r\n return true;\r\n }\r\n\r\n expect(type, value = null, message = \"Invalid expression\") {\r\n const token = this.peek();\r\n if (!token || token.type !== type || (value !== null && token.value !== value)) {\r\n throw new CalcError(message);\r\n }\r\n return this.consume();\r\n }\r\n\r\n parse() {\r\n if (this.tokens.length === 0) throw new CalcError(\"Enter an expression\");\r\n const value = this.parseExpression();\r\n if (this.peek()) throw new CalcError(\"Invalid expression\");\r\n return value;\r\n }\r\n\r\n parseExpression() {\r\n return this.parseAdditive();\r\n }\r\n\r\n parseAdditive() {\r\n let left = this.parseMultiplicative();\r\n\r\n while (true) {\r\n if (this.match(\"operator\", \"+\")) {\r\n left += this.parseMultiplicative();\r\n } else if (this.match(\"operator\", \"-\")) {\r\n left -= this.parseMultiplicative();\r\n } else {\r\n break;\r\n }\r\n }\r\n\r\n return left;\r\n }\r\n\r\n parseMultiplicative() {\r\n let left = this.parseUnary();\r\n\r\n while (true) {\r\n if (this.match(\"operator\", \"*\")) {\r\n left *= this.parseUnary();\r\n } else if (this.match(\"operator\", \"\/\")) {\r\n const divisor = this.parseUnary();\r\n if (divisor === 0) throw new CalcError(\"Cannot divide by zero\");\r\n left \/= divisor;\r\n } else {\r\n break;\r\n }\r\n }\r\n\r\n return left;\r\n }\r\n\r\n parseUnary() {\r\n if (this.match(\"operator\", \"+\")) return +this.parseUnary();\r\n if (this.match(\"operator\", \"-\")) return -this.parseUnary();\r\n return this.parsePower();\r\n }\r\n\r\n parsePower() {\r\n let base = this.parsePostfix();\r\n if (this.match(\"operator\", \"^\")) {\r\n const exponent = this.parseUnary();\r\n const result = Math.pow(base, exponent);\r\n if (Number.isNaN(result)) throw new CalcError(\"Power operation is outside the real-number domain\");\r\n base = result;\r\n }\r\n return base;\r\n }\r\n\r\n parsePostfix() {\r\n let value = this.parsePrimary();\r\n\r\n while (true) {\r\n if (this.match(\"operator\", \"!\")) {\r\n value = factorial(value);\r\n } else if (this.match(\"operator\", \"%\")) {\r\n value \/= 100;\r\n } else {\r\n break;\r\n }\r\n }\r\n\r\n return value;\r\n }\r\n\r\n parsePrimary() {\r\n const token = this.peek();\r\n if (!token) throw new CalcError(\"Expression is incomplete\");\r\n\r\n if (token.type === \"number\") {\r\n this.consume();\r\n return token.value;\r\n }\r\n\r\n if (token.type === \"identifier\") {\r\n this.consume();\r\n const name = token.value;\r\n\r\n if (CONSTANT_NAMES.has(name)) {\r\n return this.resolveConstant(name);\r\n }\r\n\r\n if (!FUNCTION_NAMES.has(name)) {\r\n throw new CalcError(`Unknown function or constant: ${name}`);\r\n }\r\n\r\n this.expect(\"lparen\", \"(\", `Expected '(' after ${name}`);\r\n const args = [];\r\n\r\n if (!this.match(\"rparen\", \")\")) {\r\n do {\r\n args.push(this.parseExpression());\r\n } while (this.match(\"comma\", \",\"));\r\n this.expect(\"rparen\", \")\", \"Check parentheses\");\r\n }\r\n\r\n return this.callFunction(name, args);\r\n }\r\n\r\n if (this.match(\"lparen\", \"(\")) {\r\n const value = this.parseExpression();\r\n this.expect(\"rparen\", \")\", \"Check parentheses\");\r\n return value;\r\n }\r\n\r\n throw new CalcError(\"Invalid expression\");\r\n }\r\n\r\n resolveConstant(name) {\r\n if (name === \"pi\") return Math.PI;\r\n if (name === \"e\") return Math.E;\r\n if (name === \"phi\") return GOLDEN_RATIO;\r\n if (name === \"ans\") return state.previousAnswer;\r\n throw new CalcError(`Unknown constant: ${name}`);\r\n }\r\n\r\n callFunction(name, args) {\r\n const requireCount = (count) => {\r\n if (args.length !== count) throw new CalcError(`${name} requires ${count} argument${count === 1 ? \"\" : \"s\"}`);\r\n };\r\n\r\n const requireAtLeast = (count) => {\r\n if (args.length < count) throw new CalcError(`${name} requires at least ${count} arguments`);\r\n };\r\n\r\n switch (name) {\r\n case \"sin\": requireCount(1); return Math.sin(toRadians(args[0]));\r\n case \"cos\": requireCount(1); return Math.cos(toRadians(args[0]));\r\n case \"tan\": {\r\n requireCount(1);\r\n const radians = toRadians(args[0]);\r\n if (Math.abs(Math.cos(radians)) < 1e-14) throw new CalcError(\"tan is undefined at this angle\");\r\n return Math.tan(radians);\r\n }\r\n case \"asin\":\r\n requireCount(1);\r\n if (args[0] < -1 || args[0] > 1) throw new CalcError(\"asin input must be between -1 and 1\");\r\n return fromRadians(Math.asin(args[0]));\r\n case \"acos\":\r\n requireCount(1);\r\n if (args[0] < -1 || args[0] > 1) throw new CalcError(\"acos input must be between -1 and 1\");\r\n return fromRadians(Math.acos(args[0]));\r\n case \"atan\": requireCount(1); return fromRadians(Math.atan(args[0]));\r\n case \"sinh\": requireCount(1); return Math.sinh(args[0]);\r\n case \"cosh\": requireCount(1); return Math.cosh(args[0]);\r\n case \"tanh\": requireCount(1); return Math.tanh(args[0]);\r\n case \"asinh\": requireCount(1); return Math.asinh(args[0]);\r\n case \"acosh\":\r\n requireCount(1);\r\n if (args[0] < 1) throw new CalcError(\"acosh input must be at least 1\");\r\n return Math.acosh(args[0]);\r\n case \"atanh\":\r\n requireCount(1);\r\n if (args[0] <= -1 || args[0] >= 1) throw new CalcError(\"atanh input must be between -1 and 1\");\r\n return Math.atanh(args[0]);\r\n case \"log\":\r\n requireCount(1);\r\n if (args[0] <= 0) throw new CalcError(\"Logarithm input must be greater than zero\");\r\n return Math.log10(args[0]);\r\n case \"ln\":\r\n requireCount(1);\r\n if (args[0] <= 0) throw new CalcError(\"Logarithm input must be greater than zero\");\r\n return Math.log(args[0]);\r\n case \"log2\":\r\n requireCount(1);\r\n if (args[0] <= 0) throw new CalcError(\"Logarithm input must be greater than zero\");\r\n return Math.log2(args[0]);\r\n case \"logb\":\r\n requireCount(2);\r\n if (args[0] <= 0) throw new CalcError(\"Logarithm input must be greater than zero\");\r\n if (args[1] <= 0 || args[1] === 1) throw new CalcError(\"Logarithm base must be positive and not equal to 1\");\r\n return Math.log(args[0]) \/ Math.log(args[1]);\r\n case \"sqrt\":\r\n requireCount(1);\r\n if (args[0] < 0) throw new CalcError(\"Square root of a negative number is not real\");\r\n return Math.sqrt(args[0]);\r\n case \"cbrt\": requireCount(1); return Math.cbrt(args[0]);\r\n case \"root\": {\r\n requireCount(2);\r\n const [x, n] = args;\r\n if (n === 0) throw new CalcError(\"Root degree cannot be zero\");\r\n if (x < 0 && !nearlyInteger(n)) throw new CalcError(\"This root is outside the real-number domain\");\r\n if (x < 0 && Math.abs(Math.round(n)) % 2 === 0) throw new CalcError(\"Even root of a negative number is not real\");\r\n if (x < 0) return -Math.pow(-x, 1 \/ n);\r\n return Math.pow(x, 1 \/ n);\r\n }\r\n case \"abs\": requireCount(1); return Math.abs(args[0]);\r\n case \"floor\": requireCount(1); return Math.floor(args[0]);\r\n case \"ceil\": requireCount(1); return Math.ceil(args[0]);\r\n case \"round\": requireCount(1); return Math.round(args[0]);\r\n case \"trunc\": requireCount(1); return Math.trunc(args[0]);\r\n case \"sign\": requireCount(1); return Math.sign(args[0]);\r\n case \"min\": requireAtLeast(1); return Math.min(...args);\r\n case \"max\": requireAtLeast(1); return Math.max(...args);\r\n case \"gcd\": requireCount(2); return integerGcd(args[0], args[1]);\r\n case \"lcm\": requireCount(2); return integerLcm(args[0], args[1]);\r\n case \"ncr\": requireCount(2); return combination(args[0], args[1]);\r\n case \"npr\": requireCount(2); return permutation(args[0], args[1]);\r\n case \"mod\": {\r\n requireCount(2);\r\n if (args[1] === 0) throw new CalcError(\"Modulo divisor cannot be zero\");\r\n return args[0] % args[1];\r\n }\r\n case \"randbetween\": {\r\n requireCount(2);\r\n let [a, b] = args;\r\n if (!nearlyInteger(a) || !nearlyInteger(b)) throw new CalcError(\"randbetween requires integer bounds\");\r\n if (a > b) [a, b] = [b, a];\r\n return Math.floor(Math.random() * (b - a + 1)) + a;\r\n }\r\n default:\r\n throw new CalcError(`Unsupported function: ${name}`);\r\n }\r\n }\r\n }\r\n\r\n function tryEvaluateRelativePercentage(tokens) {\r\n if (tokens.length < 4) return null;\r\n const last = tokens[tokens.length - 1];\r\n if (last.type !== \"operator\" || last.value !== \"%\") return null;\r\n\r\n let depth = 0;\r\n const candidates = [];\r\n\r\n for (let i = 0; i < tokens.length - 1; i += 1) {\r\n const token = tokens[i];\r\n if (token.type === \"lparen\") depth += 1;\r\n if (token.type === \"rparen\") depth -= 1;\r\n\r\n if (depth === 0 && token.type === \"operator\" && (token.value === \"+\" || token.value === \"-\") && i > 0) {\r\n const previous = tokens[i - 1];\r\n const isUnary = previous.type === \"operator\" || previous.type === \"lparen\" || previous.type === \"comma\";\r\n if (!isUnary) candidates.push(i);\r\n }\r\n }\r\n\r\n if (candidates.length !== 1) return null;\r\n\r\n const operatorIndex = candidates[0];\r\n const leftTokens = tokens.slice(0, operatorIndex);\r\n const rightTokens = tokens.slice(operatorIndex + 1);\r\n if (!leftTokens.length || !rightTokens.length) return null;\r\n\r\n const base = new Parser(leftTokens).parse();\r\n const fraction = new Parser(rightTokens).parse();\r\n return tokens[operatorIndex].value === \"+\"\r\n ? base + (base * fraction)\r\n : base - (base * fraction);\r\n }\r\n\r\n function evaluateExpression(expression) {\r\n const tokens = tokenize(expression);\r\n const relativePercentageResult = tryEvaluateRelativePercentage(tokens);\r\n const parser = new Parser(tokens);\r\n let result = relativePercentageResult ?? parser.parse();\r\n\r\n if (Number.isNaN(result)) throw new CalcError(\"Result is not a real number\");\r\n if (!Number.isFinite(result)) throw new CalcError(\"Result is outside the supported numeric range\");\r\n\r\n result = roundFloatingNoise(normalizeNegativeZero(result));\r\n return result;\r\n }\r\n\r\n \/* =========================================================\r\n 08. RESULT FORMATTING\r\n ========================================================== *\/\r\n function formatExponent(exponent) {\r\n return exponent >= 0 ? `+${exponent}` : `${exponent}`;\r\n }\r\n\r\n function formatNormal(value) {\r\n const precision = state.precision === \"auto\" ? null : Number(state.precision);\r\n let normalized = normalizeNegativeZero(value);\r\n\r\n if (precision !== null) {\r\n normalized = Number(normalized.toFixed(precision));\r\n } else {\r\n normalized = roundFloatingNoise(normalized);\r\n }\r\n\r\n const absolute = Math.abs(normalized);\r\n if (absolute !== 0 && (absolute >= 1e15 || absolute < 1e-9)) {\r\n return normalized.toExponential(12).replace(\/\\.0+e\/, \"e\").replace(\/(\\.\\d*?[1-9])0+e\/, \"$1e\");\r\n }\r\n\r\n const raw = String(normalized);\r\n if (\/e\/i.test(raw)) return raw;\r\n\r\n const [integerPart, decimalPart] = raw.split(\".\");\r\n const sign = integerPart.startsWith(\"-\") ? \"-\" : \"\";\r\n const integerDigits = sign ? integerPart.slice(1) : integerPart;\r\n const grouped = integerDigits.replace(\/\\B(?=(\\d{3})+(?!\\d))\/g, \",\");\r\n return `${sign}${grouped}${decimalPart ? `.${decimalPart}` : \"\"}`;\r\n }\r\n\r\n function formatScientific(value) {\r\n if (value === 0) return \"0\";\r\n const digits = state.precision === \"auto\" ? 10 : clamp(Number(state.precision), 1, 12);\r\n const [coefficient, exponent] = value.toExponential(digits).split(\"e\");\r\n return `${Number(coefficient)} \u00d7 10^${Number(exponent)}`;\r\n }\r\n\r\n function formatEngineering(value) {\r\n if (value === 0) return \"0\";\r\n const exponent = Math.floor(Math.log10(Math.abs(value)) \/ 3) * 3;\r\n const coefficient = value \/ Math.pow(10, exponent);\r\n const digits = state.precision === \"auto\" ? 10 : clamp(Number(state.precision), 1, 12);\r\n const rounded = Number(coefficient.toPrecision(digits));\r\n return `${rounded} \u00d7 10^${exponent}`;\r\n }\r\n\r\n function formatResult(value) {\r\n if (!isFiniteNumber(value)) return \"Error\";\r\n if (state.numberFormat === \"scientific\") return formatScientific(value);\r\n if (state.numberFormat === \"engineering\") return formatEngineering(value);\r\n return formatNormal(value);\r\n }\r\n\r\n \/* =========================================================\r\n 09. INPUT EDITING\r\n ========================================================== *\/\r\n function getInputSelection() {\r\n const start = dom.expressionInput.selectionStart ?? dom.expressionInput.value.length;\r\n const end = dom.expressionInput.selectionEnd ?? start;\r\n return { start, end };\r\n }\r\n\r\n function setInputCursor(position) {\r\n requestAnimationFrame(() => {\r\n dom.expressionInput.focus();\r\n dom.expressionInput.setSelectionRange(position, position);\r\n });\r\n }\r\n\r\n function replaceSelection(text, cursorOffset = text.length) {\r\n const input = dom.expressionInput;\r\n const { start, end } = getInputSelection();\r\n const before = input.value.slice(0, start);\r\n const after = input.value.slice(end);\r\n\r\n input.value = before + text + after;\r\n state.expression = input.value;\r\n state.justEvaluated = false;\r\n const nextPosition = start + cursorOffset;\r\n setInputCursor(nextPosition);\r\n updateLivePreview();\r\n }\r\n\r\n function insertText(text) {\r\n if (state.justEvaluated && \/^[0-9.(A-Za-z]\/.test(text) && ![\"pi\", \"e\", \"phi\", \"ans\"].includes(text)) {\r\n clearCurrentExpression(false);\r\n } else if (state.justEvaluated && \/^[+\\-*\/^%]\/.test(text)) {\r\n dom.expressionInput.value = String(state.result);\r\n state.expression = dom.expressionInput.value;\r\n dom.expressionInput.setSelectionRange(dom.expressionInput.value.length, dom.expressionInput.value.length);\r\n }\r\n\r\n replaceSelection(text);\r\n }\r\n\r\n function smartParenthesis() {\r\n const value = dom.expressionInput.value;\r\n const { start } = getInputSelection();\r\n const before = value.slice(0, start);\r\n const opens = (before.match(\/\$\/g) || []).length;\r\n const closes = (before.match(\/\$\/g) || []).length;\r\n const previous = before.trim().slice(-1);\r\n\r\n const shouldClose = opens > closes && \/[\\dA-Za-z)!%]\/.test(previous);\r\n insertText(shouldClose ? \")\" : \"(\");\r\n }\r\n\r\n function backspaceInput() {\r\n const input = dom.expressionInput;\r\n const { start, end } = getInputSelection();\r\n\r\n if (start !== end) {\r\n input.setRangeText(\"\", start, end, \"end\");\r\n } else if (start > 0) {\r\n const before = input.value.slice(0, start);\r\n const knownSuffixes = [\"sqrt(\", \"asinh(\", \"acosh(\", \"atanh(\", \"sinh(\", \"cosh(\", \"tanh(\", \"asin(\", \"acos(\", \"atan(\", \"log2(\", \"floor(\", \"ceil(\", \"round(\", \"trunc(\", \"sign(\", \"sin(\", \"cos(\", \"tan(\", \"log(\", \"ln(\", \"abs(\", \"gcd(\", \"lcm(\", \"ncr(\", \"npr(\", \"mod(\", \"min(\", \"max(\", \"root(\"];\r\n const suffix = knownSuffixes.find(item => before.endsWith(item));\r\n const deleteCount = suffix ? suffix.length : 1;\r\n input.setRangeText(\"\", start - deleteCount, start, \"end\");\r\n }\r\n\r\n state.expression = input.value;\r\n state.justEvaluated = false;\r\n updateLivePreview();\r\n input.focus();\r\n }\r\n\r\n function clearCurrentExpression(resetResult = true) {\r\n dom.expressionInput.value = \"\";\r\n state.expression = \"\";\r\n state.justEvaluated = false;\r\n dom.previewOutput.textContent = \"\";\r\n if (resetResult) {\r\n state.result = 0;\r\n dom.resultOutput.textContent = \"0\";\r\n }\r\n clearMessage();\r\n dom.expressionInput.focus();\r\n }\r\n\r\n function toggleSign() {\r\n const input = dom.expressionInput;\r\n const { start, end } = getInputSelection();\r\n\r\n if (start !== end) {\r\n const selected = input.value.slice(start, end);\r\n input.setRangeText(`-(${selected})`, start, end, \"end\");\r\n } else if (input.value.trim()) {\r\n input.value = `-(${input.value})`;\r\n input.setSelectionRange(input.value.length, input.value.length);\r\n } else if (state.result !== 0) {\r\n input.value = String(-state.result);\r\n input.setSelectionRange(input.value.length, input.value.length);\r\n } else {\r\n input.value = \"-\";\r\n input.setSelectionRange(1, 1);\r\n }\r\n\r\n state.expression = input.value;\r\n state.justEvaluated = false;\r\n updateLivePreview();\r\n input.focus();\r\n }\r\n\r\n function wrapCurrentExpression(prefix, suffix = \")\") {\r\n const input = dom.expressionInput;\r\n const { start, end } = getInputSelection();\r\n\r\n if (start !== end) {\r\n const selected = input.value.slice(start, end);\r\n input.setRangeText(`${prefix}${selected}${suffix}`, start, end, \"end\");\r\n } else if (input.value.trim()) {\r\n input.value = `${prefix}${input.value}${suffix}`;\r\n input.setSelectionRange(input.value.length, input.value.length);\r\n } else if (state.justEvaluated || state.result !== 0) {\r\n input.value = `${prefix}${state.result}${suffix}`;\r\n input.setSelectionRange(input.value.length, input.value.length);\r\n } else {\r\n input.value = prefix + suffix;\r\n const cursor = prefix.length;\r\n input.setSelectionRange(cursor, cursor);\r\n }\r\n\r\n state.expression = input.value;\r\n state.justEvaluated = false;\r\n updateLivePreview();\r\n input.focus();\r\n }\r\n\r\n \/* =========================================================\r\n 10. EVALUATION & LIVE PREVIEW\r\n ========================================================== *\/\r\n function updateLivePreview() {\r\n state.expression = dom.expressionInput.value;\r\n clearMessage();\r\n\r\n if (!state.expression.trim()) {\r\n dom.previewOutput.textContent = \"\";\r\n return;\r\n }\r\n\r\n try {\r\n const result = evaluateExpression(state.expression);\r\n dom.previewOutput.textContent = `= ${formatResult(result)}`;\r\n } catch {\r\n dom.previewOutput.textContent = \"\";\r\n }\r\n }\r\n\r\n function evaluateCurrentExpression() {\r\n const expression = dom.expressionInput.value.trim();\r\n if (!expression) {\r\n showMessage(\"Enter an expression\", \"error\");\r\n return;\r\n }\r\n\r\n try {\r\n const result = evaluateExpression(expression);\r\n state.result = result;\r\n state.previousAnswer = result;\r\n state.justEvaluated = true;\r\n state.lastEvaluation = { expression, result };\r\n\r\n dom.resultOutput.textContent = formatResult(result);\r\n dom.previewOutput.textContent = \"\";\r\n clearMessage();\r\n\r\n addHistory(expression, result);\r\n } catch (error) {\r\n const message = error instanceof CalcError ? error.message : \"Invalid expression\";\r\n showMessage(message, \"error\");\r\n dom.previewOutput.textContent = \"\";\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 11. SHIFT \/ SECOND FUNCTIONS\r\n ========================================================== *\/\r\n function setSecondMode(enabled) {\r\n state.secondMode = Boolean(enabled);\r\n dom.shiftIndicator.classList.toggle(\"is-active\", state.secondMode);\r\n dom.shiftButton.classList.toggle(\"key-shifted\", state.secondMode);\r\n dom.shiftButton.setAttribute(\"aria-pressed\", String(state.secondMode));\r\n\r\n document.querySelectorAll(\".shiftable\").forEach(button => {\r\n if (state.secondMode) {\r\n button.textContent = button.dataset.shiftLabel || button.textContent;\r\n\r\n if (button.dataset.shiftInsert) button.dataset.insert = button.dataset.shiftInsert;\r\n else delete button.dataset.insert;\r\n\r\n if (button.dataset.shiftAction) button.dataset.action = button.dataset.shiftAction;\r\n else delete button.dataset.action;\r\n } else {\r\n button.textContent = button.dataset.normalLabel || button.textContent;\r\n\r\n if (button.dataset.normalInsert) button.dataset.insert = button.dataset.normalInsert;\r\n else delete button.dataset.insert;\r\n\r\n if (button.dataset.normalAction) button.dataset.action = button.dataset.normalAction;\r\n else delete button.dataset.action;\r\n }\r\n });\r\n }\r\n\r\n \/* =========================================================\r\n 12. MEMORY\r\n ========================================================== *\/\r\n function resolveCurrentNumericValue() {\r\n const expression = dom.expressionInput.value.trim();\r\n if (expression) return evaluateExpression(expression);\r\n return state.result;\r\n }\r\n\r\n function updateMemoryIndicator() {\r\n dom.memoryIndicator.classList.toggle(\"is-active\", state.memory !== 0);\r\n dom.memoryIndicator.title = state.memory !== 0 ? `Memory: ${formatResult(state.memory)}` : \"Memory is empty\";\r\n }\r\n\r\n function memoryAction(action) {\r\n try {\r\n switch (action) {\r\n case \"memory-clear\":\r\n state.memory = 0;\r\n showMessage(\"Memory cleared\", \"success\");\r\n break;\r\n case \"memory-recall\":\r\n insertText(String(state.memory));\r\n showMessage(\"Memory recalled\", \"success\");\r\n break;\r\n case \"memory-store\":\r\n state.memory = resolveCurrentNumericValue();\r\n showMessage(\"Value stored in memory\", \"success\");\r\n break;\r\n case \"memory-add\":\r\n state.memory += resolveCurrentNumericValue();\r\n showMessage(\"Added to memory\", \"success\");\r\n break;\r\n case \"memory-subtract\":\r\n state.memory -= resolveCurrentNumericValue();\r\n showMessage(\"Subtracted from memory\", \"success\");\r\n break;\r\n default:\r\n return;\r\n }\r\n state.memory = roundFloatingNoise(state.memory);\r\n updateMemoryIndicator();\r\n } catch (error) {\r\n showMessage(error instanceof CalcError ? error.message : \"Unable to use memory\", \"error\");\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 13. HISTORY\r\n ========================================================== *\/\r\n function loadHistory() {\r\n if (!state.historyPersistence) {\r\n state.history = [];\r\n return;\r\n }\r\n\r\n const raw = safeStorageGet(STORAGE_KEYS.history);\r\n if (!raw) return;\r\n\r\n try {\r\n const parsed = JSON.parse(raw);\r\n if (Array.isArray(parsed)) {\r\n state.history = parsed\r\n .filter(item => item && typeof item.expression === \"string\" && isFiniteNumber(item.result))\r\n .slice(0, MAX_HISTORY);\r\n }\r\n } catch {\r\n state.history = [];\r\n }\r\n }\r\n\r\n function persistHistory() {\r\n if (!state.historyPersistence) {\r\n safeStorageRemove(STORAGE_KEYS.history);\r\n return;\r\n }\r\n safeStorageSet(STORAGE_KEYS.history, JSON.stringify(state.history.slice(0, MAX_HISTORY)));\r\n }\r\n\r\n function addHistory(expression, result) {\r\n const entry = {\r\n id: `${Date.now()}-${Math.random().toString(36).slice(2, 8)}`,\r\n expression,\r\n result,\r\n timestamp: Date.now()\r\n };\r\n\r\n state.history.unshift(entry);\r\n state.history = state.history.slice(0, MAX_HISTORY);\r\n persistHistory();\r\n renderHistory();\r\n }\r\n\r\n function renderHistory() {\r\n dom.historyList.innerHTML = \"\";\r\n\r\n if (!state.history.length) {\r\n const empty = document.createElement(\"div\");\r\n empty.className = \"history-empty\";\r\n empty.textContent = \"Your completed calculations will appear here.\";\r\n dom.historyList.appendChild(empty);\r\n return;\r\n }\r\n\r\n const fragment = document.createDocumentFragment();\r\n\r\n state.history.forEach(entry => {\r\n const item = document.createElement(\"article\");\r\n item.className = \"history-item\";\r\n item.dataset.historyId = entry.id;\r\n\r\n const expressionButton = document.createElement(\"button\");\r\n expressionButton.className = \"history-expression\";\r\n expressionButton.type = \"button\";\r\n expressionButton.textContent = entry.expression;\r\n expressionButton.title = \"Load expression\";\r\n expressionButton.dataset.historyAction = \"expression\";\r\n\r\n const resultButton = document.createElement(\"button\");\r\n resultButton.className = \"history-result\";\r\n resultButton.type = \"button\";\r\n resultButton.textContent = `= ${formatResult(entry.result)}`;\r\n resultButton.title = \"Use result\";\r\n resultButton.dataset.historyAction = \"result\";\r\n\r\n const time = document.createElement(\"time\");\r\n time.className = \"history-time\";\r\n time.dateTime = new Date(entry.timestamp).toISOString();\r\n time.textContent = new Date(entry.timestamp).toLocaleTimeString([], { hour: \"2-digit\", minute: \"2-digit\" });\r\n\r\n const removeButton = document.createElement(\"button\");\r\n removeButton.className = \"history-delete\";\r\n removeButton.type = \"button\";\r\n removeButton.ariaLabel = \"Delete history entry\";\r\n removeButton.title = \"Delete\";\r\n removeButton.textContent = \"\u00d7\";\r\n removeButton.dataset.historyAction = \"delete\";\r\n\r\n item.append(expressionButton, resultButton, time, removeButton);\r\n fragment.appendChild(item);\r\n });\r\n\r\n dom.historyList.appendChild(fragment);\r\n }\r\n\r\n function handleHistoryClick(event) {\r\n const button = event.target.closest(\"button[data-history-action]\");\r\n if (!button) return;\r\n\r\n const item = button.closest(\".history-item\");\r\n const entry = state.history.find(historyEntry => historyEntry.id === item?.dataset.historyId);\r\n if (!entry) return;\r\n\r\n const action = button.dataset.historyAction;\r\n\r\n if (action === \"delete\") {\r\n state.history = state.history.filter(historyEntry => historyEntry.id !== entry.id);\r\n persistHistory();\r\n renderHistory();\r\n return;\r\n }\r\n\r\n if (action === \"expression\") {\r\n dom.expressionInput.value = entry.expression;\r\n state.expression = entry.expression;\r\n state.justEvaluated = false;\r\n dom.expressionInput.focus();\r\n dom.expressionInput.setSelectionRange(entry.expression.length, entry.expression.length);\r\n updateLivePreview();\r\n }\r\n\r\n if (action === \"result\") {\r\n insertText(String(entry.result));\r\n }\r\n\r\n closeMobileHistory();\r\n }\r\n\r\n function clearHistory() {\r\n state.history = [];\r\n persistHistory();\r\n renderHistory();\r\n showMessage(\"History cleared\", \"success\");\r\n }\r\n\r\n \/* =========================================================\r\n 14. COPY & FRACTION\r\n ========================================================== *\/\r\n async function copyResult() {\r\n const text = String(state.result);\r\n if (!text || !isFiniteNumber(state.result)) {\r\n showMessage(\"Nothing to copy\", \"error\");\r\n return;\r\n }\r\n\r\n try {\r\n if (navigator.clipboard && window.isSecureContext) {\r\n await navigator.clipboard.writeText(text);\r\n } else {\r\n const helper = document.createElement(\"textarea\");\r\n helper.value = text;\r\n helper.setAttribute(\"readonly\", \"\");\r\n helper.style.position = \"absolute\";\r\n helper.style.left = \"-9999px\";\r\n document.body.appendChild(helper);\r\n helper.select();\r\n const copied = document.execCommand(\"copy\");\r\n helper.remove();\r\n if (!copied) throw new Error(\"Copy failed\");\r\n }\r\n showMessage(\"Copied\", \"success\");\r\n } catch {\r\n showMessage(\"Copy is not available in this browser\", \"error\");\r\n }\r\n }\r\n\r\n function decimalToFraction(value, maxDenominator = 100000) {\r\n if (!isFiniteNumber(value)) return null;\r\n if (nearlyInteger(value)) return `${Math.round(value)}\/1`;\r\n\r\n const sign = value < 0 ? -1 : 1;\r\n let x = Math.abs(value);\r\n let h1 = 1, h0 = 0, k1 = 0, k0 = 1;\r\n let bestH = 0, bestK = 1;\r\n\r\n for (let i = 0; i < 40; i += 1) {\r\n const a = Math.floor(x);\r\n const h2 = a * h1 + h0;\r\n const k2 = a * k1 + k0;\r\n if (k2 > maxDenominator) break;\r\n bestH = h2;\r\n bestK = k2;\r\n if (Math.abs(value - sign * bestH \/ bestK) < 1e-12) break;\r\n h0 = h1; h1 = h2;\r\n k0 = k1; k1 = k2;\r\n x = 1 \/ (x - a);\r\n if (!Number.isFinite(x)) break;\r\n }\r\n\r\n const gcd = integerGcd(bestH, bestK);\r\n return `${sign * (bestH \/ gcd)}\/${bestK \/ gcd}`;\r\n }\r\n\r\n function showFraction() {\r\n if (!isFiniteNumber(state.result)) {\r\n showMessage(\"No numeric result available\", \"error\");\r\n return;\r\n }\r\n const fraction = decimalToFraction(state.result);\r\n showMessage(`Fraction: ${fraction}`, \"success\");\r\n }\r\n\r\n \/* =========================================================\r\n 15. THEMES & SETTINGS\r\n ========================================================== *\/\r\n function applyTheme(theme, persist = true) {\r\n state.theme = theme === \"light\" ? \"light\" : \"dark\";\r\n dom.html.dataset.theme = state.theme;\r\n dom.themeSelect.value = state.theme;\r\n dom.themeButton.title = state.theme === \"dark\" ? \"Switch to light theme\" : \"Switch to dark theme\";\r\n if (persist) safeStorageSet(STORAGE_KEYS.theme, state.theme);\r\n }\r\n\r\n function applyAngleMode(mode, persist = true) {\r\n if (![\"DEG\", \"RAD\", \"GRAD\"].includes(mode)) return;\r\n state.angleMode = mode;\r\n dom.angleIndicator.textContent = mode;\r\n document.querySelectorAll(\"[data-angle]\").forEach(button => {\r\n button.setAttribute(\"aria-pressed\", String(button.dataset.angle === mode));\r\n });\r\n if (persist) safeStorageSet(STORAGE_KEYS.angle, mode);\r\n updateLivePreview();\r\n }\r\n\r\n function applyNumberFormat(format, persist = true) {\r\n if (![\"normal\", \"scientific\", \"engineering\"].includes(format)) return;\r\n state.numberFormat = format;\r\n dom.formatSelect.value = format;\r\n dom.formatIndicator.textContent = format.toUpperCase();\r\n if (persist) safeStorageSet(STORAGE_KEYS.format, format);\r\n dom.resultOutput.textContent = formatResult(state.result);\r\n renderHistory();\r\n updateLivePreview();\r\n }\r\n\r\n function applyPrecision(precision, persist = true) {\r\n const allowed = new Set([\"auto\", \"4\", \"6\", \"8\", \"10\", \"12\"]);\r\n state.precision = allowed.has(String(precision)) ? String(precision) : \"auto\";\r\n dom.precisionSelect.value = state.precision;\r\n if (persist) safeStorageSet(STORAGE_KEYS.precision, state.precision);\r\n dom.resultOutput.textContent = formatResult(state.result);\r\n renderHistory();\r\n updateLivePreview();\r\n }\r\n\r\n function applyHistoryPersistence(value, persist = true) {\r\n state.historyPersistence = value === true || value === \"on\";\r\n dom.historyPersistenceSelect.value = state.historyPersistence ? \"on\" : \"off\";\r\n if (persist) safeStorageSet(STORAGE_KEYS.historyPersistence, state.historyPersistence ? \"on\" : \"off\");\r\n if (!state.historyPersistence) safeStorageRemove(STORAGE_KEYS.history);\r\n else persistHistory();\r\n }\r\n\r\n function openSettings() {\r\n dom.settingsBackdrop.hidden = false;\r\n dom.closeSettingsButton.focus();\r\n }\r\n\r\n function closeSettings() {\r\n dom.settingsBackdrop.hidden = true;\r\n dom.settingsButton.focus();\r\n }\r\n\r\n function resetSettings() {\r\n applyTheme(window.matchMedia?.(\"(prefers-color-scheme: light)\").matches ? \"light\" : \"dark\");\r\n applyAngleMode(\"DEG\");\r\n applyNumberFormat(\"normal\");\r\n applyPrecision(\"auto\");\r\n applyHistoryPersistence(true);\r\n showMessage(\"Settings reset\", \"success\");\r\n }\r\n\r\n function loadSettings() {\r\n const preferredTheme = window.matchMedia?.(\"(prefers-color-scheme: light)\").matches ? \"light\" : \"dark\";\r\n applyTheme(safeStorageGet(STORAGE_KEYS.theme) || preferredTheme, false);\r\n applyAngleMode(safeStorageGet(STORAGE_KEYS.angle) || \"DEG\", false);\r\n applyNumberFormat(safeStorageGet(STORAGE_KEYS.format) || \"normal\", false);\r\n applyPrecision(safeStorageGet(STORAGE_KEYS.precision) || \"auto\", false);\r\n applyHistoryPersistence(safeStorageGet(STORAGE_KEYS.historyPersistence) !== \"off\", false);\r\n }\r\n\r\n \/* =========================================================\r\n 16. APPLICATION MODES\r\n ========================================================== *\/\r\n function setApplicationMode(mode) {\r\n state.currentMode = mode === \"converter\" ? \"converter\" : \"scientific\";\r\n const scientific = state.currentMode === \"scientific\";\r\n dom.scientificWorkspace.hidden = !scientific;\r\n dom.converterWorkspace.hidden = scientific;\r\n dom.scientificModeButton.setAttribute(\"aria-pressed\", String(scientific));\r\n dom.converterModeButton.setAttribute(\"aria-pressed\", String(!scientific));\r\n if (scientific) dom.expressionInput.focus();\r\n }\r\n\r\n \/* =========================================================\r\n 17. UNIT CONVERTER DATA & ENGINE\r\n ========================================================== *\/\r\n const UNIT_DATA = {\r\n Length: {\r\n base: \"m\",\r\n formula: \"Converted through metres\",\r\n units: {\r\n mm: { label: \"Millimetres (mm)\", factor: 0.001 },\r\n cm: { label: \"Centimetres (cm)\", factor: 0.01 },\r\n m: { label: \"Metres (m)\", factor: 1 },\r\n km: { label: \"Kilometres (km)\", factor: 1000 },\r\n in: { label: \"Inches (in)\", factor: 0.0254 },\r\n ft: { label: \"Feet (ft)\", factor: 0.3048 },\r\n yd: { label: \"Yards (yd)\", factor: 0.9144 },\r\n mi: { label: \"Miles (mi)\", factor: 1609.344 }\r\n }\r\n },\r\n Mass: {\r\n base: \"kg\",\r\n formula: \"Converted through kilograms\",\r\n units: {\r\n mg: { label: \"Milligrams (mg)\", factor: 1e-6 },\r\n g: { label: \"Grams (g)\", factor: 0.001 },\r\n kg: { label: \"Kilograms (kg)\", factor: 1 },\r\n oz: { label: \"Ounces (oz)\", factor: 0.028349523125 },\r\n lb: { label: \"Pounds (lb)\", factor: 0.45359237 }\r\n }\r\n },\r\n Temperature: {\r\n base: \"C\",\r\n formula: \"Uses exact temperature offset\/scale formulas\",\r\n units: {\r\n C: { label: \"Celsius (\u00b0C)\" },\r\n F: { label: \"Fahrenheit (\u00b0F)\" },\r\n K: { label: \"Kelvin (K)\" }\r\n }\r\n },\r\n Area: {\r\n base: \"m2\",\r\n formula: \"Converted through square metres\",\r\n units: {\r\n m2: { label: \"Square metres (m\u00b2)\", factor: 1 },\r\n km2: { label: \"Square kilometres (km\u00b2)\", factor: 1e6 },\r\n ft2: { label: \"Square feet (ft\u00b2)\", factor: 0.09290304 },\r\n acre: { label: \"Acres\", factor: 4046.8564224 },\r\n hectare: { label: \"Hectares\", factor: 10000 }\r\n }\r\n },\r\n Volume: {\r\n base: \"L\",\r\n formula: \"Converted through litres (US customary cup\/gallon)\",\r\n units: {\r\n mL: { label: \"Millilitres (mL)\", factor: 0.001 },\r\n L: { label: \"Litres (L)\", factor: 1 },\r\n cup: { label: \"US cups\", factor: 0.2365882365 },\r\n gallon: { label: \"US gallons\", factor: 3.785411784 }\r\n }\r\n },\r\n Speed: {\r\n base: \"mps\",\r\n formula: \"Converted through metres per second\",\r\n units: {\r\n mps: { label: \"Metres\/second (m\/s)\", factor: 1 },\r\n kmh: { label: \"Kilometres\/hour (km\/h)\", factor: 0.2777777777777778 },\r\n mph: { label: \"Miles\/hour (mph)\", factor: 0.44704 }\r\n }\r\n },\r\n Time: {\r\n base: \"s\",\r\n formula: \"Converted through seconds\",\r\n units: {\r\n s: { label: \"Seconds\", factor: 1 },\r\n min: { label: \"Minutes\", factor: 60 },\r\n h: { label: \"Hours\", factor: 3600 },\r\n d: { label: \"Days\", factor: 86400 }\r\n }\r\n }\r\n };\r\n\r\n function temperatureToCelsius(value, unit) {\r\n if (unit === \"C\") return value;\r\n if (unit === \"F\") return (value - 32) * 5 \/ 9;\r\n if (unit === \"K\") return value - 273.15;\r\n return value;\r\n }\r\n\r\n function celsiusToTemperature(value, unit) {\r\n if (unit === \"C\") return value;\r\n if (unit === \"F\") return value * 9 \/ 5 + 32;\r\n if (unit === \"K\") return value + 273.15;\r\n return value;\r\n }\r\n\r\n function convertUnits(category, value, fromUnit, toUnit) {\r\n const group = UNIT_DATA[category];\r\n if (!group) throw new Error(\"Unknown category\");\r\n\r\n if (category === \"Temperature\") {\r\n const celsius = temperatureToCelsius(value, fromUnit);\r\n const result = celsiusToTemperature(celsius, toUnit);\r\n if (toUnit === \"K\" && result < 0) throw new CalcError(\"Temperature cannot be below absolute zero\");\r\n return result;\r\n }\r\n\r\n const from = group.units[fromUnit];\r\n const to = group.units[toUnit];\r\n if (!from || !to) throw new Error(\"Unknown unit\");\r\n return value * from.factor \/ to.factor;\r\n }\r\n\r\n function populateConverterCategories() {\r\n dom.converterCategory.innerHTML = \"\";\r\n Object.keys(UNIT_DATA).forEach(category => {\r\n const option = document.createElement(\"option\");\r\n option.value = category;\r\n option.textContent = category;\r\n dom.converterCategory.appendChild(option);\r\n });\r\n dom.converterCategory.value = \"Length\";\r\n populateConverterUnits();\r\n }\r\n\r\n function populateConverterUnits() {\r\n const category = dom.converterCategory.value;\r\n const group = UNIT_DATA[category];\r\n dom.converterFrom.innerHTML = \"\";\r\n dom.converterTo.innerHTML = \"\";\r\n\r\n Object.entries(group.units).forEach(([key, data]) => {\r\n const fromOption = document.createElement(\"option\");\r\n fromOption.value = key;\r\n fromOption.textContent = data.label;\r\n dom.converterFrom.appendChild(fromOption);\r\n\r\n const toOption = fromOption.cloneNode(true);\r\n dom.converterTo.appendChild(toOption);\r\n });\r\n\r\n const keys = Object.keys(group.units);\r\n dom.converterFrom.value = keys[0];\r\n dom.converterTo.value = keys[Math.min(1, keys.length - 1)];\r\n dom.converterFormula.textContent = group.formula;\r\n updateConverter();\r\n }\r\n\r\n function updateConverter() {\r\n const value = Number(dom.converterValue.value);\r\n if (!Number.isFinite(value)) {\r\n dom.converterResult.textContent = \"Enter a valid number\";\r\n return;\r\n }\r\n\r\n try {\r\n const result = convertUnits(\r\n dom.converterCategory.value,\r\n value,\r\n dom.converterFrom.value,\r\n dom.converterTo.value\r\n );\r\n dom.converterResult.textContent = formatNormal(roundFloatingNoise(result));\r\n } catch (error) {\r\n dom.converterResult.textContent = error instanceof CalcError ? error.message : \"Conversion error\";\r\n }\r\n }\r\n\r\n function swapConverterUnits() {\r\n const from = dom.converterFrom.value;\r\n dom.converterFrom.value = dom.converterTo.value;\r\n dom.converterTo.value = from;\r\n updateConverter();\r\n }\r\n\r\n \/* =========================================================\r\n 18. MOBILE HISTORY\r\n ========================================================== *\/\r\n function openMobileHistory() {\r\n dom.historyPanel.classList.add(\"is-open\");\r\n dom.mobileHistoryBackdrop.hidden = false;\r\n }\r\n\r\n function closeMobileHistory() {\r\n dom.historyPanel.classList.remove(\"is-open\");\r\n dom.mobileHistoryBackdrop.hidden = true;\r\n }\r\n\r\n \/* =========================================================\r\n 19. CALCULATOR BUTTON ACTIONS\r\n ========================================================== *\/\r\n function handleCalculatorButton(button) {\r\n const action = button.dataset.action;\r\n const insert = button.dataset.insert;\r\n\r\n if (insert !== undefined) {\r\n insertText(insert);\r\n if (state.secondMode && button.classList.contains(\"shiftable\")) setSecondMode(false);\r\n return;\r\n }\r\n\r\n switch (action) {\r\n case \"evaluate\":\r\n evaluateCurrentExpression();\r\n break;\r\n case \"clear\":\r\n clearCurrentExpression(true);\r\n break;\r\n case \"backspace\":\r\n backspaceInput();\r\n break;\r\n case \"smart-parenthesis\":\r\n smartParenthesis();\r\n break;\r\n case \"toggle-sign\":\r\n toggleSign();\r\n break;\r\n case \"shift\":\r\n setSecondMode(!state.secondMode);\r\n break;\r\n case \"square\":\r\n wrapCurrentExpression(\"(\", \")^2\");\r\n break;\r\n case \"cube\":\r\n wrapCurrentExpression(\"(\", \")^3\");\r\n break;\r\n case \"reciprocal\":\r\n wrapCurrentExpression(\"1\/(\", \")\");\r\n break;\r\n case \"random\":\r\n insertText(String(Math.random()));\r\n break;\r\n case \"memory-clear\":\r\n case \"memory-recall\":\r\n case \"memory-add\":\r\n case \"memory-subtract\":\r\n case \"memory-store\":\r\n memoryAction(action);\r\n break;\r\n default:\r\n break;\r\n }\r\n\r\n if (state.secondMode && button.classList.contains(\"shiftable\")) setSecondMode(false);\r\n }\r\n\r\n \/* =========================================================\r\n 20. KEYBOARD INPUT\r\n ========================================================== *\/\r\n function flashMatchingKey(key) {\r\n const selectorMap = {\r\n \"+\": '[data-insert=\"+\"]',\r\n \"-\": '[data-insert=\"-\"]',\r\n \"*\": '[data-insert=\"\u00d7\"]',\r\n \"\/\": '[data-insert=\"\u00f7\"]',\r\n \"^\": '[data-insert=\"^\"]',\r\n \"%\": '[data-insert=\"%\"]',\r\n \"(\": '[data-insert=\"(\"]',\r\n \")\": '[data-insert=\")\"]',\r\n \".\": '[data-insert=\".\"]'\r\n };\r\n\r\n const selector = \/\\d\/.test(key) ? `[data-insert=\"${key}\"]` : selectorMap[key];\r\n if (!selector) return;\r\n const button = document.querySelector(selector);\r\n if (!button) return;\r\n button.classList.add(\"is-flashed\");\r\n window.setTimeout(() => button.classList.remove(\"is-flashed\"), 120);\r\n }\r\n\r\n function handleKeyboard(event) {\r\n if (state.currentMode !== \"scientific\") return;\r\n if (dom.settingsBackdrop.hidden === false) return;\r\n\r\n const inputFocused = document.activeElement === dom.expressionInput;\r\n if (!inputFocused) return;\r\n\r\n if (event.key === \"Enter\") {\r\n event.preventDefault();\r\n evaluateCurrentExpression();\r\n return;\r\n }\r\n\r\n if (event.key === \"Escape\") {\r\n event.preventDefault();\r\n clearCurrentExpression(true);\r\n return;\r\n }\r\n\r\n if (event.key === \"Backspace\") {\r\n event.preventDefault();\r\n backspaceInput();\r\n return;\r\n }\r\n\r\n const permitted = \/^[0-9+\\-*\/^().,%]$\/;\r\n if (permitted.test(event.key)) {\r\n event.preventDefault();\r\n const displayKey = event.key === \"*\" ? \"\u00d7\" : event.key === \"\/\" ? \"\u00f7\" : event.key;\r\n insertText(displayKey);\r\n flashMatchingKey(event.key);\r\n return;\r\n }\r\n\r\n if (\/^[A-Za-z]$\/.test(event.key)) {\r\n \/\/ Let browser type function names naturally into the focused input.\r\n return;\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 21. EVENT BINDINGS\r\n ========================================================== *\/\r\n function bindEvents() {\r\n document.querySelectorAll(\".calc-key, .tiny-button\").forEach(button => {\r\n if (button.dataset.angle) {\r\n button.addEventListener(\"click\", () => applyAngleMode(button.dataset.angle));\r\n } else {\r\n button.addEventListener(\"click\", () => handleCalculatorButton(button));\r\n }\r\n });\r\n\r\n dom.expressionInput.addEventListener(\"input\", () => {\r\n state.expression = dom.expressionInput.value;\r\n state.justEvaluated = false;\r\n updateLivePreview();\r\n });\r\n\r\n dom.expressionInput.addEventListener(\"keydown\", handleKeyboard);\r\n\r\n dom.copyButton.addEventListener(\"click\", copyResult);\r\n dom.fractionButton.addEventListener(\"click\", showFraction);\r\n dom.themeButton.addEventListener(\"click\", () => applyTheme(state.theme === \"dark\" ? \"light\" : \"dark\"));\r\n\r\n dom.scientificModeButton.addEventListener(\"click\", () => setApplicationMode(\"scientific\"));\r\n dom.converterModeButton.addEventListener(\"click\", () => setApplicationMode(\"converter\"));\r\n\r\n dom.historyList.addEventListener(\"click\", handleHistoryClick);\r\n dom.clearHistoryButton.addEventListener(\"click\", clearHistory);\r\n dom.mobileHistoryButton.addEventListener(\"click\", openMobileHistory);\r\n dom.mobileHistoryBackdrop.addEventListener(\"click\", closeMobileHistory);\r\n\r\n dom.settingsButton.addEventListener(\"click\", openSettings);\r\n dom.closeSettingsButton.addEventListener(\"click\", closeSettings);\r\n dom.doneSettingsButton.addEventListener(\"click\", closeSettings);\r\n dom.resetSettingsButton.addEventListener(\"click\", resetSettings);\r\n\r\n dom.settingsBackdrop.addEventListener(\"click\", event => {\r\n if (event.target === dom.settingsBackdrop) closeSettings();\r\n });\r\n\r\n dom.themeSelect.addEventListener(\"change\", () => applyTheme(dom.themeSelect.value));\r\n dom.formatSelect.addEventListener(\"change\", () => applyNumberFormat(dom.formatSelect.value));\r\n dom.precisionSelect.addEventListener(\"change\", () => applyPrecision(dom.precisionSelect.value));\r\n dom.historyPersistenceSelect.addEventListener(\"change\", () => applyHistoryPersistence(dom.historyPersistenceSelect.value));\r\n\r\n dom.converterCategory.addEventListener(\"change\", populateConverterUnits);\r\n dom.converterValue.addEventListener(\"input\", updateConverter);\r\n dom.converterFrom.addEventListener(\"change\", updateConverter);\r\n dom.converterTo.addEventListener(\"change\", updateConverter);\r\n dom.swapUnitsButton.addEventListener(\"click\", swapConverterUnits);\r\n\r\n window.addEventListener(\"resize\", () => {\r\n if (window.innerWidth > 820) closeMobileHistory();\r\n });\r\n }\r\n\r\n \/* =========================================================\r\n 22. SELF-TESTS\r\n ========================================================== *\/\r\n function runSelfTests() {\r\n const originalMode = state.angleMode;\r\n const tests = [\r\n [\"2+2\", 4],\r\n [\"2+3*4\", 14],\r\n [\"(2+3)*4\", 20],\r\n [\"10\/2+3\", 8],\r\n [\"2^3\", 8],\r\n [\"2^3^2\", 512],\r\n [\"sqrt(144)\", 12],\r\n [\"5!\", 120],\r\n [\"0!\", 1],\r\n [\"log(100)\", 2],\r\n [\"ln(e)\", 1],\r\n [\"0.1+0.2\", 0.3],\r\n [\"ncr(5,2)\", 10],\r\n [\"npr(5,2)\", 20],\r\n [\"logb(8,2)\", 3],\r\n [\"200*10%\", 20],\r\n [\"200+10%\", 220],\r\n [\"200-10%\", 180],\r\n [\"2(3+4)\", 14],\r\n [\"2pi\", 2 * Math.PI],\r\n [\"(2+3)(4+5)\", 45],\r\n [\"-5+10\", 5],\r\n [\"2^-3\", 0.125],\r\n [\"sqrt(0)\", 0]\r\n ];\r\n\r\n const failures = [];\r\n\r\n try {\r\n state.angleMode = \"DEG\";\r\n tests.push([\"sin(30)\", 0.5], [\"cos(60)\", 0.5], [\"tan(45)\", 1]);\r\n\r\n for (const [expression, expected] of tests) {\r\n const actual = evaluateExpression(expression);\r\n if (Math.abs(actual - expected) > 1e-10 * Math.max(1, Math.abs(expected))) {\r\n failures.push({ expression, expected, actual });\r\n }\r\n }\r\n\r\n state.angleMode = \"RAD\";\r\n const radActual = evaluateExpression(\"sin(pi\/2)\");\r\n if (Math.abs(radActual - 1) > 1e-10) failures.push({ expression: \"sin(pi\/2)\", expected: 1, actual: radActual });\r\n\r\n const errorTests = [\"1\/0\", \"sqrt(-1)\", \"log(0)\", \"log(-5)\", \"(-5)!\"];\r\n for (const expression of errorTests) {\r\n let threw = false;\r\n try {\r\n evaluateExpression(expression);\r\n } catch {\r\n threw = true;\r\n }\r\n if (!threw) failures.push({ expression, expected: \"error\", actual: \"no error\" });\r\n }\r\n } finally {\r\n state.angleMode = originalMode;\r\n }\r\n\r\n if (failures.length) {\r\n console.warn(\"NOVA calculator self-test failures:\", failures);\r\n }\r\n }\r\n\r\n \/* =========================================================\r\n 23. INITIALIZATION\r\n ========================================================== *\/\r\n function initialize() {\r\n loadSettings();\r\n loadHistory();\r\n renderHistory();\r\n populateConverterCategories();\r\n bindEvents();\r\n updateMemoryIndicator();\r\n setSecondMode(false);\r\n setApplicationMode(\"scientific\");\r\n dom.resultOutput.textContent = formatResult(0);\r\n runSelfTests();\r\n dom.expressionInput.focus();\r\n }\r\n\r\n initialize();\r\n <\/script>\r\n<\/body>\r\n<\/html>\r\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>NOVA Scientific Calculator Precision workspace NOVA Scientific Scientific Converter \u2315 \u25d0 \u2699 DEG M 2nd NORMAL a\/b Copy Expression 0 DEG RAD GRAD MC MR M+ M\u2212 MS 2nd ( ) ( ) \u03c0 e sin cos tan sinh cosh tanh x\u00b2 x\u00b3 x\u02b8 \u221ax \u221bx \u02b8\u221ax 10\u02e3 e\u02e3 2\u02e3 log ln log\u2082 |x| x! […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"elementor_canvas","meta":{"footnotes":""},"class_list":["post-67","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/pages\/67","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=67"}],"version-history":[{"count":4,"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/pages\/67\/revisions"}],"predecessor-version":[{"id":71,"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=\/wp\/v2\/pages\/67\/revisions\/71"}],"wp:attachment":[{"href":"https:\/\/anthoniabirthguide.online\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=67"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}